Hunger. What it is and what you can do about it.

Posted: December 17, 2012 in energy metabolism, hunger, low-carbohydrate diet, Protein
Tags: , ,

The reporter from Men’s Health asked me: “You finish dinner, even a satisfying low-carb dinner,” — he is a low-carb person himself — “you are sure you ate enough but you are still hungry. What do you do?”  I gave him good advice. “Think of a perfectly broiled steak or steamed lobster with butter, some high protein, relatively high fat meal that you usually like.  If that doesn’t sound good, you are not hungry.  You may want to keep eating. You may want something sweet.  You may want to feel something rolling around in your mouth, but you are not hungry.  Find something else to do — push-ups are good.  If the steak does sound good, you may want to eat. Practically speaking, it’s a good idea to keep hard-boiled eggs, cans of tuna fish around (and, of course, not keep cookies in the house).” I think this is good practical advice. It comes from the satiating effects of protein food sources, or perhaps the non-satiating, or reinforcing effect of carbohydrate. But the more general question is: What is hunger?

We grow up thinking that hunger is somehow our body’s way of telling us that we need food but, for most of us that is not usually the case.  Few of us are so fit, or have so little body fat, or are so active that our bodies start calling for energy if we miss lunch.  Conversely, those of us who really like food generally hold to the philosophy that “any fool can eat when they’re hungry;” passing up a really good chocolate mousse just because you are not hungry is like … well, I don’t know what it’s like.  Of course, if you are on a low-carb diet, you may pass it up for other reasons, or at least not want to eat too much.

Getting to the point here, if I presented you with a multiple choice question that asked what hunger is, the answer would be “all of the above.” We feel hunger when we haven’t eaten for a while. We may feel hunger if the food looks good or if we are in a social situation in which eating is going on, the congressional prayer breakfast, or looking at the petits fours that the caterer put in the lobby at an obesity seminar.

Friedman buffet

The coffee break at Jeffrey Friedman’s seminar on obesity at Downstate Medical Center. No kidding.

 Or we may eat because we think it is time to eat. This point was made by the Restoration poet and rake, John Wilmot, Earl of Rochester.  Rochester is famous for his bawdy poetry which is raunchy even by today’s standards (must be over eighteen to follow this link) but his Satyr against Reason and Mankind makes fun of dumb rules and phony reason:

My reason is my friend, yours is a cheat;
Hunger calls out, my reason bids me eat;
Perversely, yours your appetite does mock:
This asks for food, that answers, “What’s o’clock?”
This plain distinction, sir, your doubt secures:
‘Tis not true reason I despise, but yours.’’

For dumb advice, you can’t beat diabetes educators.  The letter to the online forum asked “My morning oatmeal spikes my blood glucose. How much carbohydrate should I have.” A diabetes expert from the site had a whole page of answers, vague recommendations with disclaimers but never saying: “don’t have any more oatmeal than that which doesn’t spike your blood glucose.”


Johnny Depp as the Earl of Rochester in The Libertine (2004).

Different people have different responses to external cues. In experiments in which subjects have a discussion with the researcher but incidentally have snacks available, thin people, not surprisingly, regulate intake by the clock on the wall, — “it’s almost lunch time” — whereas overweight people are less sensitive to this input.

The psychologist B. F. Skinner described the problem in a typically dense way.

“I am hungry” may be equivalent to “I have hunger pangs,” and if the verbal community had some means of observing the contractions of the stomach associated with pangs, it could pin the response to these stimuli alone. It may also be equivalent to “I am eating actively.” A person who observes that he is eating voraciously may say, “I really am hungry,” or, in retrospect, “I was hungrier than I thought,” dismissing other evidence as unreliable.

  “I am hungry” may also be equivalent to “It has been a long time since I have had anything to eat,” although the expression is most likely to be used in describing future behavior: “If I miss my dinner, I shall be hungry.”

 What he is getting at here is that whatever the actual causes of eating behavior, the behavior itself may precede the “motivation to eat.”  In other words, we may feel like eating or feel real hunger pangs but we tend to identify those feelings that come along with eating behavior as the cause of the behavior.

“I am hungry” may also be equivalent to “I feel like eating” in the sense of “I have felt this way before when I have started to eat.” It may be equivalent to… “I am thinking of things I like to eat”…. To say, “I am hungry,” may be to report several or all of these conditions. . . .”

The point is that “hungry” only means you are in a situation in which you are used to eating.  It doesn’t mean that feeling hungry will make you eat, or, more important, that you have to eat.

Lessons from Vagotomy.

The vagus nerve contains many nerve fibers that provide communication between the brain and other parts of the body (a nerve is a collection of nerve cells or neurons whose long extensions or axons are referred to as fibers).  Cells that send signals from the brain to distant organs are called efferent. Efferent fibers in the vagus nerve regulate the digestive tract — enlargement of the stomach, secretions from the pancreas  accommodate a larger volume of food (known to doctors as accommodation). However, most of the fibers in the vagus nerve are sensory afferents (afferents carry information from the body to the brain) providing sensations of satiety and hunger as well as feeling of discomfort.


Vagotomy, cutting the vagus nerve, was practiced as a means of controlling ulcers and is still a target, at least experimentally, for treating obesity. Dr. John Kral, Professor of Surgery at Downstate Medical Center, who has performed such operations, described to me how patients were upset and complained that they had lost their appetite. He had to explain that you do not have to eat all the time, that nothing will happen if you miss a few meals.

Hunger is a sign that you are used to eating in a particular time or situation. You are not required to answer the signal.

“You eat too much because you are fat.”

There is currently strong tendency to think of hunger in terms of hormones, emphasizing regulation by the hypothalamus analogous to temperature regulation.  The hormones are referred to as orexigenic, increasing appetite (from the Greek; the Greek equivalent of bon appetit is kali orexi), or anorexigenic, depressing appetite. While this is part of the picture, in the analysis of eating, it leads to some confusion because, in the end, for animals and humans, outside of a laboratory setup, behavior trumps hormones. The analogy is also not great in that animals (and humans) regulate their temperature hormonally only to a small extent.  The major control of temperature is behavioral: we put on clothes and we hide in caves.

An important aspect of this problem is the attempt to understand the error in “a calorie is a calorie.”  One critique of the energy balance model runs something like this: dietary carbohydrate ➛ insulin ➛ ( other hormones ➛) increased appetite ➛ greater consumption. In the extreme case, some explanations might boil down to “you don’t get fat because you eat; you eat because you got fat.” On the face of it, this is nonsensical (which is why I am not attributing it to anybody in particular) but presumably it means that the hormonal secretion from adipose tissue encourages eating.  The limitation of such an explanation is that it mixes up metabolism with behavior and implicitly accepts the idea that calories are what count, that is, the effect of macronutrients  affects how much you eat (total energy) rather than regulating the efficiency with which it is turned to fat.  Macronutrients clearly differ in their effect on satiety and hormones may affect your appetite.   However, regardless of what your hormonal state, if there is no food, you will not increase consumption but metabolism will keep running.  Also, the effects of insulin are not so clear cut. Whereas metabolically, insulin is anabolic, at the level of behavior it is probably anorexigenic in most cases.

The so-called metabolic advantage, less weight gain per calorie, where it exists, is a metabolic effect. The most likely mechanism is that, because of the effect of insulin on rates of reaction, anabolic steps may increase fat accumulation before competing feedback can catch up.  We explained this in the context of what is referred to as non-equilibrium thermodynamics, which recognizes the importance of rates as well as energy. The first 3 pages and Figure 1 in our paper explains the idea. (The rest of the paper would be considered technical, theoretical, tedious, or pretentious, depending on your taste).

What Can you do about it?

The suggestion at the beginning of this post is to make sure you know what kind of hunger you are talking about.  In this, behavioral psychology stresses the difference between “tastes good” and the technical term, reinforcing which only means that the food increases the probability that you will keep eating.  Anecdotally, we all have the experience of somebody (else?) saying “I don’t know why I ate that. It wasn’t very good.”

However little you have to eat, it is certainly bad advice to eat if you are not hungry. Professional nutritionists, even those on the Atkins website, are always telling you to have a good breakfast. Why you would specifically want to have a good anything if you are trying to lose weight is not easy to answer.  They say, of course, that you will eat too much at the next meal as if, in the morning, you can make the rational decision to eat breakfast in the face of not wanting to eat but, at noon, you are suddenly under the inexorable influence of urges beyond your control. It might be reasonable to say “if you find that you eat too much at lunch when you don’t eat breakfast…,” Many people have the opposite reaction — sometimes food is more reinforcing than satiating — and reasonableness is not the usual style of traditional nutritional advice anyway.

Portion Control.

 Yon Cassius has a lean and hungry look,

He thinks too much; such men are dangerous.

— William Shakespeare, Julius Caesar

In a previous post,  I described how nutritionists recommend “portion control” as if it were some great new scientific principle. What it actually means is “self-control” the usual moralistic approach to dieting. I suggested that it is this nagging that leads to the sense of deprivation that all higher (and maybe lower) animals feel if they are told that something is verboten.  Getting away from this attitude is probably the main psychological benefit of low-carbohydrate diets.  I recommended taking advantage of the lack of proscription on quantity in low-carb diets to actually eat less, namely, to have small portions (of low-carb food) and then, if you still want more, to have more. Following the points above, however, feeling hungry because you want to have a lean and hungry feel if not look, is different from feeling hungry because you are compelled to stick to somebody’s diet.


The only thing that people in nutrition agree on is the value of exercise.  While it is not as important as diet for weight loss, it does interact with diet and has obvious benefit.  One question is when to have meals in relation to exercise.  Although the details are outside my area of expertise, and it is likely that it is an individual thing — there is some good guide in the following old joke.

 The couple come to the doctor and don’t want to have any more children but they don’t want any artificial methods of birth control.  The doctor recommends exercise.

Husband: Before or after?

Doctor: Instead of.

  1. Lovely. Enjoyable as prose as much as science. I’m a big fan of John Wilmot myself and recommend “Rochester’s Monkey” the long-suppressed biography that Graham Greene wrote in the 1930s as an introduction.

  2. Marilyn says:

    If the perfectly broiled steak or the lobster with butter sounds good after I’ve just eaten a meal, that means that if I’d have eaten one of those instead to begin with, I probably wouldn’t be looking around for something else. 🙂 But alas, while we might eat something equally nourishing most days, we don’t usually eat something equally tasty. This is why I think the food reward theory is, excuse me, bass ackwards. In my experience, the better something is, the more satisfying it is, and the less I’m inclined to go looking for something else when I’ve finished eating. We went out to a nice restaurant the other night, and I ordered duck. The portion wasn’t much bigger than a hamburger patty. It was served with a bit of sauce, a bit of mashed potato, and some cooked kale. We had some creme broule for dessert. The food was fabulously prepared. It wasn’t a huge meal. (But neither was it a Barbie-size “gourmet” meal.) I didn’t feel stuffed. But I felt completely satisfied

    • rdfeinman says:

      Yes. That is part of the picture but conversely, as I mentioned, some of us feel that “any fool can eat when they’re hungry.” A fundamental idea of behavioral psychology is that the reinforcement value of a stimulus (defined by its effect on future behavior) is different than its hedonic value (“reward” is a little ambiguous). Some food is tasty but not overly reinforcing which may be some kind of definition of haute cuisine.

  3. Helen Hilts, MD says:

    Hi Richard, I think the problem is not false hunger or a lack of protein , but a lack of sufficient calories. Say that the average, not so active person burns about 2000 kcals a day. The human body only wants about 20% of it’s calories from protein. Someone who is eating low carb must get about 70% of calories from fat or they will starve. We can gorge on protein for a few days and then we develop an aversion to it. Many readers of Men’s Health are working out fairly vigorously, or they are just young men, so they would need even more than 1500-1600 calories a day from a source other than protein, meaning fat or carbs. In my own experience eating low carb for my diabetes, that means consciously adding fat to my meals, 1-3 tablespoons per meal in addition to the fats naturally found in the food. (The other source of calories could be alcohol, I suppose.) I think the guy is not eating enough fat.

    Helen Hilts MD

    • rdfeinman says:

      Hi Helen,
      I don’t think the editor was asking about a real problem so much as the general principle. I agree with your analysis but practically speaking, I think high protein sources provide fat unless you adhere to the idea of “lean meat,” an expression which conjures up one of those tasteless cuts of beef whose name I am not sure of, or those un-marbelled logic-defying pork chops from pigs bred to have no fat — if anything is supposed to be fat, it is a pig.

      • bigfatketogirl says:

        The Chinese call Belly Pork “5 layers of heaven”. We now call it that in our house. Since I went keto to control my metabolic syndrome, one small piece of belly pork is as much protein as I am “allowed” in a meal.

      • rdfeinman says:

        Do you want to explain?

      • bigfatketogirl says:

        Explain? 5 layers of heaven or my keto WOE? LOL

        5 layers because it is meat,fat,meat,fat,rind. Heaven because it is fatty,calorific and tasty. 🙂

        My WOE for a short while now (3 weeks) has been ketogenic diet. I am pre-diabetic (probably diabetic if I hadn’t been low carb for 4 years). I can’t loose weight (lost really fast 4 years ago but can’t get any more weight off even by going extreme low calorie). I am 31 year old female, heavy build (broad shoulders, long legs), 6ft1inch tall and approx 240lbs. Because of my heavy build I am heavier than I look but I am still US size 16-18. My problem is that my dawn effect blood sugar keeps getting higher and higher through the day until mid afternoon, even if I fast. No matter whether I eat or not it has normalised to 95 by early evening, but is up to 120 again in the morning and climbs up to 130-140 around lunch time of its own accord whether I eat or not… So for 3 weeks I have been on a strict ketogenic diet. My low carb diet did not result in blood/urine ketones. I figured it was because it was too heavy in protein. So now I have limited myself to 60g protein per day. I aim for 50g and if I go a bit over or I need a snack because I am hungry then I have a few grams leftover for cream cheese and celery.

        My rules are – very low carb, 60g protein per day, balance out the protein with at least 80% calories from fat to reach the ketogenic ratios, always eat something in the morning even if I am not hungry (I figured eating would help combat the morning effect of rising blood sugar?) and always eat something if I am genuinely hungry… So. I’m typically having strawberries and avocado with cream for breakfast, no lunch because I’m not hungry, small piece of meat (e.g. belly pork) with copious amounts of low carb veggies with either butter on the veg or cream sauce. For desert I’ll have strawberries and cream or homemade low carb ice cream, but I am rarely hungry so am not having desert much. Usually I only have 2 meals a day. I’ve eaten more veggies being keto than I have since I was eating low fat. Weight loss is marginal so far but its only been 3 weeks. Scales show 2-3lb loss but who knows until it settles out over the month… Waist in inches hasn’t changed much (maybe 0.5inch down). I thought it had but then it crept back up. I am definitely keto now though. Blood ketones are 1.5-2 in the evening and 0.3-0.7 in the morning. So I’ll give it another few weeks and see where I’m at.

        I don’t know much about the diabetic morning effect, the dawn phenomenon. It is difficult to find info on this as there are conflicting opinions. It still happens even though I’ve been low carb for years so no idea if it can be improved. I’ve heard drinking alcohol before bedtime improves morning blood sugars, but since I think that I am pre-diabetic due to insulin resistance of the liver then I don’t want to pickle my liver with alcohol. I figure a glass of red wine occasionally wouldn’t hurt but for now I am being strict… Keto-adaptation is better after 2 weeks apparently so the good stuff should really be happening here on in…

        Anyway, coffee break over. Cheers for the blog. It’s very interesting to read. 🙂

      • rdfeinman says:

        Thanks for the explanation and the vision of heaven.

  4. Laura says:

    Hello Prof…
    Dr Friedman was here in the UK to collect a prize so he gave use a prize acceptance lecture….he says there is NO obesity epidemic. It has been hyped by the media and is an artefact of using the BMI to quantify a continuous trait like body weight. Perhaps that explains the FEAST laid out for the coffee break……
    I am very interested in feeding behaviour. I think however that it is important to distinguish between hunger and appetite. Hunger is what makes us initiate eating. I really think we rarely eperience true hunger in this day and age. Appetite is teh drive to eat after we have commenced eating and it might be what would make many of us want to continue eating even after a good low carb meal. I know I have an almost infinite capacity to eat after I have eaten. Hunger is much easier to control than appetite….. I find it really easy to fast and do so for more than 20 hours every day but once I break the fast a new demon is unleashed…what do you think?

    • rdfeinman says:

      I think that the idea of an obesity epidemic is exaggerated and is part of the general attitude toward food that historians will look back on as some kind of psychotic frenzy like we imagine overtaking communities in the middle ages. Fructose is toxic? Aspartame is a killer? A little self-flagellation will surely make it all go away. There are, however, many people strongly dissatisfied with their ability to control what they want their body weight to be and that is very real. The psychological burden, not helped by lipophobia and fructophobia, is tremendous.
      Hunger is what makes us initiate eating. That’s what you think. Skinner’s point is that you don’t know that. Hunger is what you say you have before eating or during eating …or even after eating “Oy, was I hungry.” His point (and my point) is that whatever the feeling is, you don’t have to answer it. We also know from psychology that the same stimulus can be reinforcing or aversive depending on the subjects control over it. The advantage to a low-carb diet is that you can do without food and consider the feeling of hunger as beneficial because you choose to; if you want to eat, you can. The hunger from a low-fat diet is imposed from without and is not so tolerable.
      The question that Skinner is really addressing is how we talk about feelings or attitudes that may be individual and that the verbal community does not have access to. In this context, I think of the following question: Who discovered color blindness, and what does it tell us about communication?
      Aside from theoretical analysis, though, we all know what you mean. Food is frequently more reinforcing that hunger-reducing — in fact, that’s one reason we might wonder if we know what hunger is. As you say, many of us can sit in front of a bowl of chocolate-chip cookies indefinitely but if one, shall we say, flies into our mouth, the whole bowl will soon be gone.

      • Alexandra M says:

        “…some kind of psychotic frenzy like we imagine overtaking communities in the middle ages.”

        But even those psychotic frenzies are thought to have had a biological cause: ergotism.

        I’m not a dualist. I don’t see how thinking can free itself from biochemistry. If a parasite like Toxoplasma gondii can change the behavior of a mouse to the point where it loses its instinctive fear of cats and actually becomes attracted to them, how can we tell what influence our own hormones have over our thinking and thus our behavior? Maybe your hormones are telling you, “Pay no attention to that hormone behind the curtain.” 😉

      • rdfeinman says:

        I’m not a dualist either and it may well be a microorganism that has changed our instinctive of food to fear but hopefully some of us can resist this infection.

    • Alexandra M says:

      ” he says there is NO obesity epidemic. It has been hyped by the media and is an artefact of using the BMI to quantify a continuous trait like body weight.”

      I don’t know about the UK, but in the US it’s got to the point where I notice people who are NOT fat. I suppose if you live in a wealthy community and don’t go outside it much you could think that the obesity epidemic is all hype. I myself was shocked one day when I went into a supermarket in a very wealthy Connecticut town by the number of “not fat” people shopping there, compared with what I see everywhere else. At least a third of the people I know and interact with every day are really overweight, not just overweight according to some BMI chart (according to which what my husband calls my “hot little body” is still 30 pounds overweight), and that one third tracks pretty closely with CDC statistics.

      • rdfeinman says:

        Obesity may be a question of definition but there is no doubt that many people are overweight and, as you say, it is geographical. New Yorkers are not particularly fat but in America which I usually describe as starting somewhere in New Jersey, people are definitely overweight. When TV and movie stars are fat, something has changed since the days when Suzanne Sommers lost a part in Starsky and Hutch because she was “too chunky.” I like her book because she obviously knows what it is about.

  5. Alexandra M says:

    Before I read “Good Calories, Bad Calories,” the best “diet” book I had ever read was “Diets Don’t Work” by Bob Schwartz. (To be clear, Schwartz’s simple book from 1996 seems to have become an elaborate franchise with on-staff acupuncturists etc – that’s not what I’m talking about.) In his book he addressed many of these stimuli that we mis-identify as hunger, things like souvenir eating and eating by the clock. I learned to eat only what I really wanted and only as much as I truly enjoyed, so my friends would be horrified when I’d put 2/3s of a small ice cream, uneaten, in the trash and astonished when I’d have only one bite of my husband’s dessert.

    I didn’t become “naturally thin,” but I’m sure I ended up a lot less fat thanks to the ideas in his book.

    • rdfeinman says:

      This all sounds desirable and you can see where it would be hard to ask where hunger fits in or even, what the motivation to eat is. What is souvenir eating?

      • Alexandra M says:

        Souvenir eating is “I’m in Rome, so I simply MUST have my fill of gelato.” Or a Carnegie Deli 2 pound pastrami sandwich because you’re visiting New York. Or any other specialty food associated with a vacation destination.

        I did eat gelato in Rome, but only a tiny cup every other day.

      • rdfeinman says:

        God, I wish I had a gelato now.

      • Sam Huff says:

        Hey, I could really go for the 2 pound pastrami sandwich, but hold the bread of course. Manyana.

        OTOH, they always gave me a stomach ache.

      • rdfeinman says:

        No pain, no gain, taste wise, that is.

  6. Alexandra M says:

    As usual, I forgot to say what what an excellent post this was. I would ask, though, that if behavior trumps hormones, is it wrong to interpret the blood sugar crash after a high carb meal as “hunger?” It wasn’t until I read Gary Taubes that I realized that my habitual “healthy” breakfast of shredded wheat (no sugar) and skim milk was the very thing making me feel ravenously hungry by 10am. I kept telling myself that I shouldn’t be hungry because I’d had a “healthy” breakfast, but I undoubtedly was.

    • rdfeinman says:

      “As usual, I forgot to say what what an excellent post this was.” Yeah, watch that.

      “…is it wrong to interpret the blood sugar crash after a high carb meal as ‘hunger?’”
      It is not wrong to say that blood sugar correlates with your description of feeling hungry (if that’s what the glucometer says) and it is undoubtedly correct that when you snarf down donuts that somebody brought to the office it was because you had a feeling you described as “hunger.” The question is whether that isn’t a description rather than an explanation. This isn’t academic in that if neither low blood sugar nor feeling hungry make you eat, then you can evolve a set of circumstances whereby you can “put 2/3s of a small ice cream, uneaten, in the trash and … have only one bite of my husband’s dessert.”

  7. Laura says:

    Thanks for your reply
    As hunter-gatherers there must have been a stimulus to make us initiate the search for food. I think is it very difficult to study normal feeding behaviour in humans in the present time as we have lost the context…I agree that we misinterpret hunger completely….I think what we call hunger was a stimulus to go off and seek eadible stuff not necessarily to eat. This is why even someone with a big appetite like me can fast easily for hours and with the knowledge that food is near at hand. in fact I do my food shopping in the fasted state, but I shop sensibly and don’t crave what I handle.
    Even more than the sight of food what I find really intrudes in my fasting is the smell of food and the sight of other people munching. But I am getting better and better at shutting this off.
    Other questions could be what drives continuous feeders like rodents to eat? or stop eating even in a lab environment when food pellets are always available? Also I raised a moth caterpillar over the summer and observed its feeding habits. It lives quite literally on its food ( bit like herbivores) and yet it ignores it for hours only to regain interest when something internal seems to trigger this…And jsut before pupating it stopped eating for a whole week!
    THis is a fascinating topic.
    THank you for introducing it.

  8. Alexandra M says:

    “New Yorkers are not particularly fat…”

    At least not south of 96th Street!

  9. Gretchen says:

    I think one problem with this topic is a lack of universally accepted definitions. If what I call “hunger” is what someone else calls “appetite,” we can have a useless discussion.

    Also, you said, “This isn’t academic in that if neither low blood sugar nor feeling hungry make you eat . . . ”

    Having low blood sugar may not “make” you eat, but if you’re really low and you don’t, you could die. This is a pretty good incentive. Anyone who is not diabetic doesn’t know what a real low feels like.

    You can perspire, shake, have difficulty standing up, have difficulty thinking, have pounding heartbeat, and finally pass out. Once you’ve experienced a serious low, you’ll correct a slight low to avoid the other.

    • rdfeinman says:

      1. It is hard to go beyond behavioral definition: hunger means you are in a situation where you have been reinforced with food.
      2. Low blood sugar has to be corrected but that is not totally overlapping with the causes of over-eating.

      • Gretchen says:

        You can define it here, but that doesn’t mean other people will use that definition. That’s what I meant. A person may read an article on another site that uses different definitions and hence conclude something that wouldn’t be true if they were using your definitions.

        Maybe there are articles out there defining these things, but I’m not familiar with them.

        One problem I have with defining hunger is that sometimes I’m not sure whether I’m hungry or not. I might feel ravenous, but if something more interesting happened, maybe a spaceship landing in my pasture, I’d lose interest in food for a bit, at least.

      • rdfeinman says:

        The behavioral definition is a description rather than a real definition and it is really part of radical behaviorism, that is the idea that much explanation of motivation is really a re-wording of the observation. He ate because he was hungry, in this view, is a kind of tautology. The import is that you have to define the conditions under which eating takes place and find a work around — keep candy out of the house, even use what behaviorists use to refer to as covert behavior: think if a steak will do it for you or not.

  10. Marilyn says:

    I wonder. Did our hunter gatherer ancestors only eat when they were seriously hungry, as in might-soon-starve-if-they-didn’t? At what point did they decide it was time to get busy and rustle up some significant lunch? Did they ever eat when they weren’t truly hungry — when there were some good-looking leftovers? when they spied a tasty-looking grub, or piece of ripe fruit as they walked along? Is it possible, even, that we have imposed set mealtimes on something we were hard-wired to do: graze?

    • rdfeinman says:

      Not my area of expertise but my intuition is that pigging out is pretty basic. Relevant is some old studies that I will have to dig up. In a decerebrate rat preparation (essentially no brain — lesion at the level of the superior colliculus), if you put something good tasting in its mouth will chew but if it is something doesn’t taste good it won’t. I may not have that exactly right but going for taste is pretty low down in evolution. On the other hand, my recollection is also that conditioning and associations with taste are, as you expect, controlled at higher brain levels.

      • Marilyn says:

        On conditioning: When her kid was still in a high chair, my Bombay “sister” fed him hot (spicy) curry. He ate it happily.

      • rdfeinman says:

        But when the kid starts to speak and says “that wasn’t so hot,” we may not agree. Skinner’s main point was that we have some inaccuracy in verbal communication about private events and therefore attributing causal effects to those events may not be a good idea.

        My main point is that you don’t want to attribute to “hunger” a causal role in what is a metabolic effect (greater efficiency in fat storage). My recollection is that conditioning is at the protein synthesis level. I think this was only done in rats but early feeding leads to reduced synthesis of capsaicin receptors.

        So, what about my question: who discovered color-blindness and why do ask the question in this context?

    • Gretchen says:

      Traditional people in New Guinea ate mostly a boring diet of sweet potatoes. But occasionally they’d have feasts in which they’d butcher a pig or pigs. When this happened, they’d all pig out. And some would get a clostridial disease (called pig-bel) that is similar to what we sheep breeders call “overeating disease” in lambs.

      So I suspect early H-Gs were the same. When they killed a mastedon, they probably overate, past the point of fullness, because they knew there might not be any more meat for weeks. No one has documented that paleolithic H-Gs got clostridial diseases, as they didn’t Tweet much.

      When you don’t know where your next meal is coming from, you’ll eat whenever food is available, hungry or not. Graduate students are a good illustration of this.

  11. Pam says:

    Hunger was a very different feeling to me on a high-carb diet than it is on a low-carb diet. On a high-carb diet it was an intensely physical sensation originating in my stomach an working its way up to my neck and mouth and head. It was accompanied by specific cravings. The word “pang” is pretty accurate to describe it. On a low-carb diet, it’s usually more of a tired or weak feeling originating in my head and it’s pretty easy to ignore. There are no cravings. If I recognize the feeling (often I don’t) then I may find myself standing in the kitchen wondering what to eat for a good period of time. Fullness is also different. On a high-carb diet, it’s a physical feeling of being stuffed (but if offered dessert I could probably find room). On a low-carb diet, food just stops tasting good, even food I really like. There may be a physical feeling if I overeat, but I usually don’t. I just lose interest in food. I’ve also noticed that if I’m eating out, the choice of cuisine seems to assume undue importance to my dining companions, while it’s usually a fairly neutral thing for me — I’d like something nutritious and filling and not over-priced! Don’t get me wrong — I love food and am considered a good cook — it’s just the difference between normal appetite and addiction! Also, breakfast is my favorite meal of the day — it’s usually pretty substantial and I couldn’t imagine going without it!

  12. Around the BMI – if I went up to the “maximum healthy” weight for my height (in BMI calculations) I would merely be sleek and plump, not nearly obese. But if I went down to the “minimum healthy” weight everyone would assume I had AIDS or anorexia – I’m quite sure I would not look, or feel, normal or healthy. I’ve weighed several kilos over that minimum in the past and people have still been concerned for me.
    Maybe obesity is more like pornography – impossible to define, but one knows it when one sees it.

  13. Robin Feinman says:

    Good article! I especially like your analogy for not eating the chocolate mousse…

  14. Bill DeWitt says:

    In my training as an addictions counselor, heavy emphasis was placed on helping other to differentiate between emotions, since many addicts conflate such diverse feelings as anger, fear and depression. Basically we taught them the words that went along with their feelings, and they were then able to address those feelings more effectively.

    In recent reading I have seen studies showing that in different cultures, colors are not differentiated as we do, simply because they don’t have the words to do so. They actually see green and blue as the same color, because their language tells them it is.

    I wonder if having accurate terms for the different states you discuss would have an effect on our perceptions of those states and lead to an increased ability to deal with them effectively.

    • rdfeinman says:

      “…we taught them the words that went along with their feelings.” Are you sure it is possible to know their feelings. The colors are especially interesting. An unusual letter to a neuroscience journal from a musician who had perfect pitch said that as he got older the pitch was changing and he was now a half-tone out of synch. This was especially troubling to him because he had always associated particular notes with colors and he was now confused.

      So, what about my question: who discovered color-blindness and why do ask the question in this context?

      • Bill DeWitt says:

        Well, of course we were teaching a group of 20-30 so knowing anyone’s individual feelings at any particular time was not the issue, but letting them learn the terms in general allowed them to begin expressing them to us, and in retrospect it appears they learned to correctly identify their feelings. I know I learned to differentiate a wider range of feelings than I had previously experienced.

        I’m not sure what you mean by color blindness. But if you mean the cultures who did not differentiate between colors, they could match hues as well as you or I, they just thought that green and blue (for instance) were shades of the same color. Here’s a link: (this is just the first link I found, it’s late)

        Why I bring it up is that if we can learn to speak of hunger in terms that differentiate between the several states that you list in your comments above, perhaps, like the children in these studies and my clients, we can use those terms to engage with the world in more effective ways. If I know that I am craving instead of hungering, or “souvenir eating” instead of craving, or any other terms that I might need to define discrete states, I can then attach unique responses to those particular sensations instead of simply treating them all the same way, either shaming myself or indulging myself or whatever my particular coping style may be.

      • rdfeinman says:

        We are not really in disagreement but rather we’re taking a different point of view. Although, as in my answer to Alexandra, I am a Skinnerian of sorts, practical uses of emotion can clearly be useful and effective in, for example, controlling eating behavior. However, when they are not effective or when they fail to explain behavior, the limitations of the descriptive power of “hunger” and the limitations of how much it is a “cause” of behavior rather than a side issue, these factors will kick in.

        Interesting link. Color-blind people, of course, are not blind in any sense but they show failure to distinguish, most commonly, between red and green which I think was Dalton’s original problem. I think, in some medical circles, “Daltonian” specifically refers to red-green color blindness but is more general in other languages (F., daltonien, Rus. daltonik but Ger, farbenblind).

    • Gretchen says:

      “In recent reading I have seen studies showing that in different cultures, colors are not differentiated as we do, simply because they don’t have the words to do so. They actually see green and blue as the same color, because their language tells them it is.”

      A long time ago, I knew someone researching that sort of thing among Mayans. They’d show them a blue-green item. The monolingual Mayan speakers would call it one color, and the monolingual Spanish speakers would call it the other color. When they showed it to the bilingual people, they got very confused.

  15. Marilyn says:

    “But when the kid starts to speak and says ‘that wasn’t so hot’ . . .” . . . .! I suppose I should have seen that coming.

    Yes, the whole matter of knowing how another person experiences things is challenging. My friend’s color blindness became apparent to his parents when he refused to wear a pink sweater — which was gray.

    • rdfeinman says:

      So, what about my question: who discovered color-blindness and why do ask the question in this context?

    • Gretchen says:

      “Yes, the whole matter of knowing how another person experiences things is challenging.”

      Yes. We tend to assume others experience the world as we do. Here’s a quote from my Type 2 book : “Alex E. described the time someone brought some scrumptious pastries to work. A thin person walked in, looked at the pastries, and said, “Oh my those look good. I wish I were hungry so I could try one.” Alex was flabbergasted. He was hungry all the time and thought everyone else was too. Only after he learned to control his blood sugar levels did his hunger abate and he learned what normal hunger is like.”

      Alex (who was very overweight; he once calculated he’d lost 4000 pounds over the course of his life but kept regaining it) just assumed his hunger was the same as everyone else’s. But I thought it was also interesting that the thin person recognized that the food looked good but didn’t want to eat it unless she was hungry, whatever that means.

  16. Alexandra M says:

    So now I’m a little confused. The argument seems to be tending toward the idea that hunger does not have a biological / biochemical basis? How then to account for the huge number of people who go on low-carb diets and are astonished to find that their incessant hunger and intrusive thoughts of food vanish? Hunger can’t be just a “cultural construct” if many people unexpectedly experience the loss of it due to a change in diet.

    The question of color blindness is an interesting one. John Dalton “discovered” it in 1792, but plenty of people could have discovered it independently, the way I did when discussing Pantone colors with a fellow architecture student in the seventies. We were trying to choose a color for a joint project, and it soon became clear that my friend couldn’t distinguish between orange and olive green. As far as language, some languages make fewer distinctions, some languages make more. My Russian painting teacher explained to me that “goluboy” is a distinguishable form of blue – a sky blue. Interestingly, the term is also used in slang to mean “gay.”

    But, within the context, you seem to be suggesting that there is a subjectivity that makes determining answers impossible. But I don’t think that’s true. When one person senses something that another can’t, that doesn’t mean that there’s a 50/50 probability that the stimulus exists. My husband and I have had this argument a few times over flowers: I say that the Delaware White azalea or the Acidanthera has a powerful fragrance and he insists that it doesn’t. I always argue that he can only claim NOT to be able to smell it, not that it isn’t there. It’s an epistemological thing.

    • rdfeinman says:

      Well, I mentioned a number of different things. Hunger is a big topic when you try (usually unsuccessfully) to stay under 2000 words. Everything has a biological/biochemical basis but one of the points I was trying to get at is that “hunger” is part of behavior and while it is tied to hormonal states it doesn’t answer the question of metabolic inefficiency as a function of macronutrients, that is, do we gain less weight per calorie on one diet or the other. I am objecting to theories that say carbohydrate, e.g., affects hormones which affect hunger which increase consumption. The reason is that hormonal response is biological and inevitable whereas consumption depends on circumstance — if there is no food, you will not eat but there may still be metabolic inefficiency.

      Once you look at behavior, however, you have to be careful — obviously I am a follower of B.F. Skinner who emphasizes that sometimes we describe “A causes B” when all we really know is “A and B,” in this case, saying “I ate so much because I was really hungry” may not have any more information than “I ate so much.” Of course, the verbal community, as Skinner liked to call it, may have similar experiences and we have a sense that we understand what kind of feelings we are talking about and, as you say, we may have common feelings when we reduce our intake on low-carb but there are limitations and in some cases, they can fall to less than 50/50.

      So, your answer on color is exactly right. Dalton, the “father of modern chemistry” was the first to describe color-blindess — in some languages, color-blind people are referred to as Daltonians. But you are right, the first case could not possibly have been at the end of the eighteenth century. It is that we rarely identify things only by their color and “green” may have good agreement as the “color” of the stuff that grows on your lawn. But, it is only when you are a chemist and might compare two solutions that differ only in color — or the Pantone charts is an even better example — that you find out that you are not talking about the same thing.

      So there are two different issues. The extent to which a stimulus is the cause of behavior and the extent to which “hunger” is really involved in response to diet. In both cases, we may not be adding information by using the idea of hunger which may be poorly defined and, among other things, may be a parallel to the biological/biochemical basis.

      I feel there is some chance that this made things clearer. Yes?

      • I’m a Daltonist and it raises interesting questions about reality and consensus. How do we know that colour-sighted people see colours the same as one another anyway? Synasthetes make different connections between colours and musical frequencies, there is no consistency when colours are interpreted that way. I have less distinction so I defer to those who have more on principle.

  17. Marilyn says:

    It has been my observation that “perfect pitch” is simply a memory that develops in some children when they start piano study young — usually before six. I’ve never known anyone for whom the pitch changed as they aged, but I DID know a woman whose perfect pitch simply went away when she went on Zoloft.

    • rdfeinman says:

      I wish I had tried to play the piano when I was five although I don’t believe your theory. I am sure it is genetic although I find your story about the woman who lost her perfect pitch very distressing. In my youth, I had a friend with perfect pitch and, it was back when mattresses really had springs and she said that most mattresses had a fundamental frequency of B-flat but that’s another story.

      • Marilyn says:

        Yes, the “singing springs” (mattress) story is completely believable to me.

        While I would agree that the ability to develop “perfect pitch” could be genetic, “perfect pitch” as we’re describing here — the ability to recognize or reproduce a “C” or a “G-sharp” or a “B-flat” or whatever out of the blue — can’t possibly be something one is born with; it has to be learned. And since I don’t recall meeting anyone with “perfect pitch” who didn’t start music lessons at somewhere below six, my feeling is that it has to be learned quite early. The musical system on which our discussions here are apparently predicated is a 12-tone equal temperament system with an A440 pitch standard — a recent, and not universal, development. “B-flat” two hundred years ago might not have been identical to the one we might hear today. Also, someone growing up with one of the various traditional Chinese or Indian music systems might recognize pitches within one of those systems, but wouldn’t even know what “B-flat” is. In all cases, it’s a matter of learning.

        I don’t know what was going on with the gentleman with the sliding scale (pun intended), but my hunch is that the woman taking the Zoloft had some deep-seated memory disturbed by the drug.

        For your reading pleasure:

        For the record, I don’t call it “perfect pitch” or “absolute pitch,” I call “pitch recognition,” which is more descriptive and takes the “magic” out of the whole thing.

      • rdfeinman says:

        Interesting links but for those of us who don’t even have good relative pitch, it’s all magic.

  18. Gretchen says:

    I decided to test the perfectly broiled steak theory of hunger. Here’s what I did.

    On Day 1, I had a very small small lobster tail with garlic butter and broccoli and spaghetti squash with butter. Normally I’d feel that was enough. I wasn’t stuffed, but I felt satisfied.

    Then I visualized a juicy steak, and it sounded delicious. Unfortunately, I didn’t have any steak in the house, the closest supermarket is 17 hours away, and we’re in the midst of an ice storm, so I had to use what I had.

    Instead of the juicy steak, I had 4 strawberries with SF whipped cream. After that, I felt full.

    I’m not sure if feeling full had to do with the extra calories in the fruit and cream or if it was because before them I was in Savory Mood, ready for seconds, and after that I was in Sweet Mood, after which something savory doesn’t sound as good, or if it was because dishing up the frozen strawberries and zapping them and eating them took just enough time to let the meal leave the stomach and trigger CCK, or something else.

    On Day 2 I had two loin lamb chops from a local farm (I usually eat only one) with all the fat, spaghetti squash with butter, and lettuce with olive oil and lemon juice.

    Then I visualized a juicy steak, and it sounded delicious. Later that evening, when I was feeling quite full, I visualized the same steak, and it still sounded delicious.

    This morning when I got up, I visualized that same steak. Even though it was beginning to go rancid, it still sounded delicious.

    I’m thinking that in my case, lusting after a perfectly broiled steak has less to do with hunger than it has to do with the fact that I haven’t had steak for a long time. If we ate steak every night, and maybe for breakfast and lunch too, boiled tripe might sound delicious.

    Maybe we should distinguish psychological hunger (desire for variety in our meals) and physiological hunger.

  19. Marilyn says:

    “. . .it’s all magic.” It’s a fascinating topic, to be sure. Even more mysterious is the phenomenon of a “savant.” Many years ago, I visited a classroom of “blind retarded” youngsters. One of them, at age 12, still hadn’t been able to learn Braille. But he could stand at the piano and play all manner of things. I picked up a toy xylophone, played a tune on it, and set it in front of him backwards. He took the mallet, played a couple of notes, stopped, turned the thing around and repeated what I had played exactly.

  20. Sugaraholics says:

    I read years ago that often thirst is the real culprit that we interpret as hunger. When I get that urge to eat, and I know it can’t be hunger, I drink a big glass of water and it magically goes away. Also, like Pavlov’s dog, just the sight or thought of certain kinds of foods make be suddenly “hungry,” ergo the ten thousand ads a day we are all subjected to for that end.

  21. Marilyn says:

    There are a lot of insults and aggravations to peoples’ stomachs that can cause or magnify feelings of hunger. Stretching a stomach by eating a larger than usual meal, especially at night, can cause some people to feel ravenous later. Irritation from acids from many different sources — vinegar, tomato sauce, citrus, raw fruits (especially under ripe fruit), soft drinks, etc. — as well as irritation from alcohol — might bring a lingering gnawing feeling of hunger. Medications of many sorts are stomach irritants, including the ones that are supposed to block acid. All these can make the question “Am I really hungry?” more difficult to sort out.

  22. Laura Dolson says:

    Are you saying that you think eating is mainly driven by external cues? And do you know if all warm-blooded creatures mainly control their body temperature behaviorally?

    • rdfeinman says:

      Eating certainly has biological causes but we don’t know what “mainly” drives eating. My main point is that eating behavior is separate from metabolism although they do interact. On the metabolic end, we want to know whether some foods are fattening and, in particular, whether energy in-energy out is right or wrong. I am suggesting — not attributing this to anybody in particular since I can’t remember who said it exactly — that saying exercise doesn’t help because it will make you eat more is not adequate explanation because eating is separate from metabolism. If you climb a large mountain but bring a small lunch, that’s all you will eat.

      The point of the post is that “hunger’ is not well defined and I cited B.F. Skinner who felt that what we are doing in saying “hunger” may be only describing that we ate a lot. People didn’t like Skinner telling them that they didn’t know what they were talking about and, since I worked in that field, I can testify that there was a group with the same irrational hatred for Skinner that lipophobes have for Dr. Atkins — the difference is that Skinner was one of the great thinkers in history and for a while was the foremost psychologist in the country (not taking anything away from Atkins).

      You don’t have to be an orthodox behaviorists, however, to recognize that we don’t really know what drives us to eat. Psychologists are not even happy with “driven by.” Biologically speaking we sometimes can’t distinguish between external and internal cues. (“Tastes good.” Is that internal or external? How about “Looks good” or even “I know you don’t see well in dark restaurants. Let me describe that to you?”) Skinner’s point was that “hunger” is a description of eating behaviors and we don’t know how they are caused.

      We are, of course, interested in macronutrients. Most of us know that sugar is highly reinforcing especially in the short term. It is one of the stimuli that dos not require deprivation. Animals and people may be reinforced by sweet whether they just ate or not. That is why we have desert after we eat.

      So the probably unsatisfying answer to your first question is that it can’t be answered as you frame it but both internal and external cues influence eating behavior.

      The second question is easier. Unless they are restrained in some way, behavior is the main way most animals control temperature. Of course, many start out with an evolutionary head start. Polar bears obviously need less inventiveness than we do in the cold.

      Finally, again, the lesson of vagotomy. Nothing will happen to you if you don’t eat all the time.

      • Laura Dolson says:

        OK, thanks — I’m largely in agreement with this, and I have no argument with Skinner on this description. (When I look back on my psychology training, all I can think about is the things we didn’t know then about the brain, etc.) Certainly it’s true that differentiating between internal and external cues is often almost impossible, especially given that it’s probably often an interaction. I think of the study that showed the added emotional valence given to food after weight loss (shown on FMRI) that went away with the addition of leptin. Is that internal or external?

        I also very much like the analogy with temperature control. Both weight and temperature are controlled very finely, but (in effect) our physiology uses our behavior to accomplish it. One question is “what happened to our weight thermostats”? As a society they are more than just a half-tone off, and the increased eating happened quite suddenly. Was it carbs in general, fructose in particular, hyperpalatable foods, BPA or other chemicals in the environment, more weight-loss dieting, viruses, disturbed gut flora, or simply, as some have claimed, “too much food around”? I don’t think it’s just one thing, but I don’t think we’re close to really knowing what the mix is.

      • rdfeinman says:

        Well, you’ve raised all the outstanding questions in nutrition presumably to insure job security for us bloggers. I’m not sure I put much stock in FMRI especially since some of what hunger (that is, eating) is fairly low down. I have to go back and relearn the animal studies but a decerebrate preparation as I recall can distinguish bad food from the good stuff.

  23. Vegard Lysne says:

    Great post Richard! Will probably write an article based on this soon 🙂

  24. Emaho says:

    Yes, great post and great comments. The whole thing read like a convolute short story – humor, sex (if you followed the links) and mystery (as in who found the color blind people? and what do you mean hunger isn’t important?)

    • rdfeinman says:

      Thanks. I don’t know if the last question was a real question.

      Anyway, this post is a chapter in my forthcoming book (2013 is my year) and, on behavior, I make the point that food is immediately reinforcing. The principle in psychology is that the time to reinforcement rather than the quality of the reinforcer is most important. This means that probably only aversive stimulation works well. Although a positive take on hunger might be that feeling hungry means that your diet is working and that you are really losing weight. Encouraging as it may be, as a guide to action (or inaction) it can’t compete with even the smell of food. You need something strongly negative.

      One of the more effective regimens is from Dr. Allen Fay, a psychiatrist in New York. It works like this. 1) You pick an amount of weight you want to lose in the next week; you can pick zero but, of course, you can’t go up. 2) You write a check for $2, 000 to (in my case) the Republican National Committee and give it to Dr. Fay. 3) If, at the end of the week, you haven’t hit the target, he mails the check. As the weigh-in day approaches, you are not hungry. Hunger, whatever that is, goes way down.

      In some cases, he said, you don’t even need money. One patient wrote a letter to a right-to-life organization. The thought they she would get on their mailing list as a supporter was sufficiently aversive to keep here on target. You pick your own threat, of course. Dr. Fay suggested the American Nazi Party but I thought that they would only buy those shabby uniforms whereas, from my perspective, the Republicans would do real damage. My relation to Dr. Fay is partly professional — although he admits that there are people who are beyond psychotherapy — and partly friend and for the technique to work you must be distant enough from the person holding the check so that he will actually mail it, but close enough that you will not consider physical violence if he does.

      • Laura Dolson says:

        “I make the point that food is immediately reinforcing.”

        It also, depending on your state, can be simultaneously positively and negatively reinforcing, which is also pretty powerful.

      • rdfeinman says:

        It also depends on circumstances and down the line its effects can be aversive — we don’t like to see the scale go up — but it may not affect behavior.

  25. Hunger as a term is a problem, because the experience of hunger is not one thing and so overloading the term hunger makes it difficult to things clearly about the matter.

    My experience is that a very apparent feature of being on a ‘normal balanced’ diet is that the feeling of an empty stomach was an independent feeling from the compulsion to eat. I could be full but the second half of the pizza still appealed. I could have an empty stomach and feel it, but not have food craving. The counterproductive correlation between these two feelings were probably the macroscopic manifestation of the regulatory disorders that were keeping me fat. By staying in ketosis, my compulsion to eat (maybe what we call hunger pangs) have been kept in check, but only when I have a reasonable energy deficit. I can eat too much fat and this seems to begat more fat eating. My sticking to only a single (high fat/medium protien/no carb) meal in the evening and starting the day with a couple of coffees (with cream) I seem to have synchronized the feeling of stomach emptiness with the compulsion to eat (around 6.00 in the evening). I undoubtedly have an empty stomach earlier, but the feeling isn’t apparent until the chemical energy from the coffees goes away. So it’s clear to me that the perception of stomach hunger interacts with the more mental or hormonal states of hunger in non obvious or non trivial ways.

    A good start for understanding hunger would be to define distinct terms for the different aspects of physical hunger and mental eating compulsion and use them.

    • rdfeinman says:

      The gist of the problem is defining hunger as a stimulus for eating and it is the impossibility of defining “distinct terms” that impedes progress. My point is that it is not useful in the discussion of problems of why we get fat.

      Skinner’s point was that what we call hunger is not a definition of a stimulus but a restatement of the observation that we just ate a lot. The reason is that we do not have experimental access to “my experience,” “feeling of an empty stomach,” “compulsion to eat,” or even “full.” All may be correlates of neuronal or biologic stimuli but because the experiences “empty stomach and feel it” and “food craving” are private events and not part of a biologic analysis, they may not help. You are sure that you “have synchronized the feeling of stomach emptiness with the compulsion to eat” but that may not apply to me. What’s “clear to me” may not be clear to the next guy.

      Again, it is important when we try to define getting fat where “hunger” is largely separate from metabolic changes.

      • Gretchen says:

        I don’t agree with Skinner that hunger is a restatement that we just ate a lot, because humans eat for many reasons, some of which have nothing to do with hunger. I agree it’s a useful concept when working with rodents that, with the exception of Mickey, can’t tell us how they felt. And if Skinner were alive today, he might refine his definition, so I don’t think we should rely on it any more than we raise our children in “Skinner boxes.”

        Imagine that I haven’t eaten for 24 hours, and I say I’m hungry. Someone brings me food (don’t I wish), but just then a rabid skunk comes into the house and tries to bite me. I don’t eat the food because I’m running out the door. Does that mean I wasn’t hungry?

      • rdfeinman says:

        “I don’t agree with Skinner that hunger is a restatement that we just ate a lot, because humans eat for many reasons, some of which have nothing to do with hunger.”

        He didn’t say that ‘if we eat it means we were hungry.’ You have it turned around. This is the opposite (or something logically different) of what is meant. He said that when we say that we were hungry, it is equivalent to an observation about eating which may or may hot have any additional information. Even Skinnerians find themselves saying, yesterday, “Gee, I ate that whole bowl of salad. I must have been really hungry.” In terms of a scientific understanding, the second sentence doesn’t add anything to the first.

        “I agree it’s a useful concept when working with rodents that, with the exception of Mickey, can’t tell us how they felt.”

        You can tell me how you felt but, the question is whether that is a cause of anything. My hunger could not have caused me to eat the whole thing since I didn’t even feel that I was hungry until afterwards.

        “And if Skinner were alive today, he might refine his definition, so I don’t think we should rely on it any more than we raise our children in ‘Skinner boxes.’”

        He might but I don’t see what would make him change his mind (or my mind). Also, I pointed out that Skinner was subject to the same hostility and myths that plagued Dr. Atkins. A Skinner Box is for animals — my contribution to behavioral psychology is the construction of a Skinner Box for crabs (Abramson CI, Feinman RD: Lever-press conditioning in the crab. Physiol Behav 1990, 48(2):267-272). Don’t laugh. The zoologists didn’t think that it could be done.

        The myth that you could put a kid in a Skinner Box comes from an article Skinner wrote for Ladies Home Journal in which he made an air-conditioned crib for his daughter (he was a serious gadgeteer). The editors of the Journal ran the story as “Baby in a Box.” He wanted to call the crib an “heir-conditioner” indicating that the man was not perfect.

        “Imagine that I haven’t eaten for 24 hours, and I say I’m hungry. Someone brings me food (don’t I wish), but just then a rabid skunk comes into the house and tries to bite me. I don’t eat the food because I’m running out the door. Does that mean I wasn’t hungry?”

        As above, you have it backwards but it does suggest that hunger is not a necessary cause of eating.

    • baerdric says:

      “A good start for understanding hunger would be to define distinct terms for the different aspects of physical hunger and mental eating compulsion and use them.”

      I think that’s exactly what I was trying to say earlier.

      • rdfeinman says:

        We all agree that that would be good. I think I am at fault for not being more precise about the problems with hunger. We can agree that there are different things we call hunger, some that correlate with when we ate, some with what the food tastes or smells like. And we all have rough ideas about what people say when they talk about their feelings. That’s all fine in every day speech but if we are going to make advance on understanding eating behavior and the control of metabolic processes we have to realize that it is probably impossible to get sufficiently precise parameters to define distinct terms. I will look for some specific examples and maybe write new post on that.

  26. Gretchen says:

    You said, “Skinner’s point was that what we call hunger is not a definition of a stimulus but a restatement of the observation that we just ate a lot.”

    Then you said that my comment that “I don’t agree with Skinner that hunger is a restatement that we just ate a lot. . . “is turning things around.

    Please clarify.

    • rdfeinman says:

      Actually, you are in agreement. We are interested in what causes what. We tend to say “I ate a lot because I was hungry,” in other words, A (some physiologic stimulus) –> B (hunger) –> C (eating). But what we know is A and B and A and C, or that A –> C and Skinner’s point is that B doesn’t add any explanatory information. So, when you say “humans eat for many reasons, some of which have nothing to do with hunger” that is in agreement that B does not have a necessary causal role in eating.

      The general idea is frequently stated as association does not prove causality — I always emphasize that more precise is that association does not necessarily prove causality, or when I was in college, they always said post hoc ergo propter hoc was not always true.

      We have to deal with the same logical problem in A –> B (obesity) –> C (diabetes) so the ADA targets B. Of course, they also don’t know what A is but A –> C and often B is hard for them to understand even when you explain that A–> B AND A–> C in those cases. But they do pretty well given what they have to work with (intellectually speaking).

      So, I was wrong. You are actually in agreement with the idea that B does not always add anything (and may even be wrong) in A –> C. In the case of hunger, though, it is the difficulty in finding measurable indicators. We may wind up saying ghrelin –> eating but if we build it into a general theory, we have to recognize that physiologic processes may move forward even if there is no food so anabolic hormones may be more important than orexigenic hormones.

  27. Gretchen says:

    It occurred to me while yawning that hunger is a lot like sleepiness. In both cases, when the condition is strong, it’s difficult to resist. But when it’s weaker, less so. And both are difficult to define.

    We can fall asleep at a boring lecture, even though we’ve had plenty of sleep, just as we can snack during a boring meeting, even though we’ve had plenty of lunch.

    In the case of sleep, we know it’s caused in part by a buildup of adenosine, and we can fight it with caffeine, which blocks adenosine receptors.

    In the case of hunger, we know it’s caused in part by a buildup of grehlin. What we need is a harmless substance to block grehlin receptors.

    • rdfeinman says:

      As a variation on your last comment, it is likely that “humans eat for many reasons, some of which have nothing to do with ghrelin.” The time course of ghrelin production undoubtedly lags behind the appearance of the unusually good-looking muffin that was presented last night but it took some serious covert behavior (as the behaviorists call it) to have only a small taste.

    • Laura Dolson says:

      I think there are a lot of physiologic urges that fit this pattern. We were talking about temperature before — if you’re a little cool, you probably don’t even think about it, but if someone were to decide to exist at, say, 95 degrees body heat, they would soon become quite preoccupied with heat and cold. If you need to pee, you can put it off for awhile, but at some point you NEED TO PEE! When people first limit food, it’s not so hard — you can distract yourself pretty easily. But weeks and months and years down the road, the need for food becomes more and more uncomfortable, and it becomes a full-time job to keep losing, or to maintain a large loss (I actually mean this literally — it’s been my observation that the few people I know who or have heard of who have been able to maintain large weight losses past the magical 5-year mark aren’t, say, working full time and raising kids, and usually neither).

  28. Sugaraholics says:

    I’m beginning my New Year’s fast for ten days which I do as a kind of internal spring cleaning. I have done this many times, and follow my progress in my journal. The first couple of days I feel hungry intermittently, and almost always because I see, think, or smell food; then day three or four I find I really don’t think much about food unless I make the mistake of reading blogs where there are lots of food pictures, recipes, etc. I’m growing to think that much of my hunger of the past was what Dr. Lance Dodes talks about regarding addictions, that is, an attempt to fill an uncomfortable place more in the brain than the belly.

    • rdfeinman says:

      We don’t usually think of eating as an addiction but there is certainly an addictive-brain component to food.

      • Sugaraholics says:

        I agree; of course the foods I would be “hungry” for are not protein but carbs; so your observation about imagining a steak works. I wonder how many people have even experienced real physical hunger in this culture–few I suspect. Even after fasting several days I don’t experience what I “think of” as hunger normally.Normally I image a food in my mind, rather than have a sensation of hunger; real hunger is to me more of a mouth experience, like thirst. BTW, after a fast the drive to eat, especially quick calories, is very strong, so one has to be on guard and eat strictly for nutrition.

  29. Laura Dolson says:

    Sugarholics, my hypothesis, based on both observations of many people over many decades and reading the obesity and weight loss literature, is that when serious hunger (however we define it; it could be simply “the impulse to eat” – it’s more evident in it’s strength than in how exactly an individual experiences it) kicks in is a lot based on how heavy you are to start with and how much weight you’ve lost. For people who are a “normal” weight, it probably kicks in fairly quickly — at least by about 5% of of body weight lost. For overweight people, at some point in the area of 10-15% of body weight loss. For obese people, they might lose weight successfully for 18-20 months, but very rarely beyond that point. How this impulse to eat manifests in the short term is simply not relevant when we are talking about a substantial weight loss, when the body is striving to regain that weight (or at least a portion of it). In my experience, people who’s bodies are responsive to carbohydrate reduction have the easiest time losing weight without undue hunger when eating a low-carb diet. A few are able to achieve and maintain very large losses. But this does not mean that hunger is not a limiting factor most people who are trying to maintain a large weight loss.

  30. Nan says:

    I absolutely agree with low carb being the best way for overweight people to lose weight. I grew up in an extended family where one side were very thin, skinny, and always trying to gain weight, the other side tending to heavier, most though not obese. What was always interesting to me was that the skinny people used the word “starving” often, but not so the heavier folks; also the skinny ones tended not to have the so-called “sweet tooth.” For me it’s been a bit of both, as I got into late middle age I put on weight quickly, couldn’t sleep, craved sweets excessively, etc. I know it’s complicated, and I’m no scientist, but my own experience of gaining weight on a “heart healthy” low fat diet 1200 cal diet proved to me that low carb is the only thing that makes sense. Hunger seems to be one of those things that needs a lot of those fascinating Fmri studies.

    • rdfeinman says:

      One of my points is that we use “hunger,” as you describe, imprecisely and, for that reason, it is unlikely to be a meaningful stimulus. In terms of understanding and clarity, fMRI is most likely to take us in the other direction — high-tech phrenology seems like not much of an exaggeration — although the pictures are fascinating however little the meaning that can be ascribed to them.

  31. What I find interesting is the association between obesity in various common brain disorders. A recent paper in Academic Pediatrics demonstrates this co-morbidity:

    Click to access 120363530-UCLA-Childhood-Obesity.pdf

    Although the exact mechanism of this connection is not clear, insulin signaling likely plays a role. The primary dietary triggers seem to be excessive fructose mainly from sugar and HFCS and high glycemic carbohydrates mainly from grains.

    Many common brain disorders have been tied to obesity, including depression, ADHD, PTSD, OCD, eating disorders, bipolar II, fibromyalgia, irritable bowel syndrome, restless leg syndrome and similar conditions. We now believe that there is a distinctive disease process at work that we call Carbohydrate Associated Reversible Brain syndrome or CARB syndrome.

    An example might be helpful. Up until about 50 years ago all depressed people lost their appetite and lost weight—this was one of the defining characteristics of the disease. Over the past 30-40 years, many depressed patients have an increased appetite and weight gain. We believe that this latter group has CARB syndrome, not true major depression.

    CARB syndrome is defined by the presence of excessive body fat (regardless of size or weight) and up to 22 brain dysfunction symptoms that overlap with many traditional mental disorders.

    The treatment is simple—remove the dietary triggers.

    • rdfeinman says:

      “The treatment is simple” Does it work?

    • Richard:

      I live and die by the sword. I am a clinician. If it doesn’t work, I am toast. I have been doing this for over 30 years, so I do have a sense of what works. My patients do give me immediate feedback. Theories are nice, but results are much better.

      We often don’t know what is going on inside the black box. If I put in A and I keep getting B (which is what I want), then I will keep using A. I keep trying to look inside the black box because if I can see the underlying mechanisms, then I might learn that using D will give me E, which is a more desirable result. I know, this is just empiric science. But what am I supposed to do? I’m married to a beautiful Greek lady!

  32. Alexandra M says:

    Have you read Sugar, Salt, Fat? It’s got some great stuff in it, but I’m becoming extremely tired of the author saying that various processed foods “…contain THREE [or FOUR or FIVE] TIMES the recommended daily maximum of saturated fat…” without ever once digressing to consider the validity of the recommendations. Perhaps the narrator using “scary voice” every time he gets to the word “fat” isn’t helping either.

    One thing I do agree with, though: You’ll consume fewer calories (and less fat, if you care about such things) if you sit down to a couple of ounces of creamy goat brie than if you sit down with an 8 ounce bag of potato chips.

    You really should read and write a review of this book!

    • rdfeinman says:

      I would like to read but I’m afraid for such a book it would be if and only if I were writing a review. I am asking around if anybody wants one. If you do care about fat or saturated fat, contrary to intuition, you’re not much worse off with a bag of pork rinds and even people who like them, like me, can’t eat more than one bag…okay, two.

      • Alexandra M says:

        The interesting point was about a study that showed that “hidden fat” was more likely to be consumed “to excess,” as in your pork rinds, which even you claim you could eat two bags of.*;jsessionid=5C58009896205C4CE1B285294AF3EB92?sequence=1

        So, interestingly, the satiety that fat normally creates HAS been undermined by [sting] Big Food.

        *Ending a sentence with a preposition is something which generally up with which I would not put.

      • rdfeinman says:

        Isn’t that study about effect of sugar on fat perception and vice-versa? All my pork-rinds are sugar free although I am guessing that they have a certain amount of glycosaminoglycans. My point, and yours I think, is that it is good to get the data rather than going with guesses. I have no problem with ending with a preposition probably part of the appeal of German to English speakers.

      • Sam Huff says:

        Ah, I have to be very careful with pork rinds, they give me diarrhea even the small bags.

  33. Dr. Feinman ~ Mother was diagnosed Type-2 at age 48 and had become overweight. Out of 6 children, 4 of us are now Type-2. All of my life I was thin, but gained weight in mid-late 50’s & tried different eating plans to no avail. 2 yrs ago at age 65, I was diagnosed Type-2 diabetic & take Metformin (500mg). Now my LDL cholesterol is elevated & was prescribed a low-dose statin.

    I follow the diet prescribed by my Internist (eliminating white bread, potatoes, pasta, etc.) & count carbs, keeping servings below 15gms & meals within 60gms, with calories ranging 1200-1600/day. At home, I eat veggies, meat/fish/fruit & whole grains (steel-cut oatmeal & 12-grain bread in moderation). As a guest at my daughter’s, I’ll have a small dessert or glass of wine 2x/mo. at the most. However, in 2-1/2 yrs. I have gained 30 lbs. despite working out at a gym with a trainer 3x/wk!!

    My cardiologist recommended the Mediterranean Diet Plan to help reduce LDL cholesterol. In researching that diet, I found your blog & am thoroughly confused. I am also desperate, but then you already know that by the fact that I am posting a comment.

    From a cell biology POV, what eating plan will WORK for me as a Type-2 diabetic?

    Thank you so much for everything you do to help diabetics. ~ Moms Hugs aka Eve

    • rdfeinman says:

      I am sorry to hear about the problems your are having. Of course, I can’t give you medical advice but from the pOV of basic science, the first thing to do in diabetes is to remove as much carbs as you can — 60 g/meal is more than I eat and I don’t have diabetes. So there is no need for oatmeal, any kind of bread or very much fruit although the best guide is if you have a glucometer, that will tell you what to eat. There are also many good resources. the Bible is Dr. Richard Bernstein’s diabetes Solution — not a page-turner but important information, Gretchen Becker’s Diabetes: the first year, Jennie Ruhl’s Diabetes 101 to name a few and there is an Atkins Diabetes Book and several websites. Serious low-carb is what you should try first and since you are taking medication, you have to find a doctor who is in sympathy. You generally have to reduce medication before you start low carb although you are lower than many people. Everybody’s different and there are really many variations on Type-2 so you have to find out what works but low-carb we call the “default” diet: try that first.

      I also don’t know your doctor but many doctors when they say Mediterranean Diet mean “I don’t know anything about nutrition and I read something in JAMA about Mediterranean diets and I can’t say ‘I don’t know’ to a patient.” You have to judge yourself whether the doctor knows about nutrition. On CVD, from a scientific point of view, the common measurement that you want is the ratio of triglycerides/HDL. (The cut-off is 3.5; you want it lower than that) This is, as far as I know much more predictive than LDL but blood glucose is the best measure of CVD risk.

      Again, I can’t give medical advice but I would challenge the doctor on statins. The literature is iffy at best and tends to say that statins do not help women and maybe nobody who hasn’t actually had a cardiovascular event. I hope this helps. Good Luck.

      • Gretchen says:

        Eve, I agree with Richard about low carb being the default diet. I also agree that we’re all different, and the important thing is finding the diet that is best for *you.* Use your meter 1 and 2 hours after eating to find the effect of food on blood glucose, and get lab lipid tests to find the effect of diet on lipid levels. Many of us aim for 15 g of carb or less per *meal.* Some can tolerate more and some need even less.

        Go to TuDiabetes to discuss this in detail with fellow patients.

  34. Thank you! Having put a husband & son through med school, I can assure you the curriculum is quite short on nutrition. Those first 2 years includes bio-chem, organic-chem, etc. that should give the basic science of what food does in a human body. Still, most MD’s are notoriously bad to their own bodies and – as you say – “don’t know” much about nutrition. Yet, it is nutrition & diet that determines so much disease & healing rates. So, go figure! That’s why I’m here seeking bio-chem answers to nutrition-related diseases.

    I do use a glucometer several times a week (ranges 115 fasting to 135 after meals). The ratio of triglycerides to HDL on my last lab is 3.27 (LDL is 119), and I have a 7.1 hemoglobin A1c. I will eliminate carbs per the books you recommended & see how that shows up in my June labs.

    As for statins, I agree with you, but both my Internist & cardiologist are adamant about that. A 2nd opinion from another cardiologist recommended doubling dosage, so I sincerely doubt there’s any who would disagree. Like it or not, big pharma has a tight grip on the medical profession.

    I really appreciate your taking time to respond to my request. Thank you so much!

  35. Razwell says:

    Hi Dr. Feinman, 🙂

    I support the work that you do ( as well as Gary Taubes).

    I think you are on solid ground. I have confirmed that the human body is indeed an open, non-equilibrium system from some of the best physics scientists who specilaize on this subtle topic such as Dr. Gavin Crooks.

    Although they do not specialze in physiology per se, they know the area of science ( from a physics point of view i.e. open, non-equilibrium thermodynamics of biological systems) this topic belongs in and understand that fat loss/gain are complex biochemical processes and not “basic thermodynamics problems” etc.

    Your consideration of free energy is right on the mark. Top guys at Caltech told me. They also told me this area of science is super subtle and a very rich and interesting area. Your Internet blogger critics are the people who are grossly uninformed.

    Take care,

  36. Shell says:


    This is the very first article on food consumption that has made perfect sense to me. I will re-post it with your permission?

  37. Dr. Feinman: As of the day I first wrote you, I decided to develop a daily meal plan based on Low Carb & Mediterranean Combined. I eliminated oatmeal, brown rice, all-grain bread or pasta, and all fruits but grapefruit or berries, and added more fish and limited intake of beef & pork. Meals have become creative cuisine limiting carbs to 30-40mg/day & calories to 1100-1300/dayFoods consumed (carbs, fat, protein & calories) and glucometer results are recorded daily in Excel.

    In 4 weeks, I lost a total of 15 lbs. & blood sugars now range throughout the day from 92 to 100 (with Metformin). Lab tests in early June should show similar results. Goal: no meds!

    Thank you so much. You can consider me one of your a “lab rats” now. {!,!}

  38. Gretchen says:

    @Bigfatketogirl: There are some oddball types of diabetes that have relatively little to do with diet or insulin resistance. So your build may not be related to your prediabetes. It might be a good idea to discuss your situation with a good endocrinologist who supports low-carb diets and see if you could get a GAD65 antibody test as well as a C-peptide test. You might also want to join some diabetes groups to see if anyone else has had similar results.

    I’m type 2, and when I fast, my BG goes up about 20 points from fasting and then goes down again and stays there. I have a friend thought to be type 2 whose BG went up if she fasted and kept going up until she ate something. She turned out to be type 1, or LADA, a form of type 1 that appears in adulthood. There’s also MODY and some other types.

  39. Anita Gandolfo says:

    As someone who was morbidly obese from early childhood and finally lost close to 200 lbs four years ago AFTER menopause, it seems to me that you’re unnecessarily complicating a clear distinction I’ve noticed between what I term ‘physical hunger’ and ‘head hunger.’

    What drove my obesity for so long was an extreme sensitivity to carbs so that within 30 min. of a meal, my overproduction of insulin would drive my blood sugar so low that I experienced extreme hunger–that was physical. It had nothing to do with my ‘wanting’ to eat more; I felt ravenous.

    But a person can’t spend a lifetime obese without developing ‘food issues’–i.e., seeing food as the enemy but also as the great comforter. THAT’S the ‘head hunger’ that is driven by situation and circumstances. I want to eat because 1) that food looks good; 2) I’m really tired, so I want the comfort of some ice cream, etc., etc.

    Low carb manages my physical hunger–and behavioral awareness helps me cope with ‘head hunger.’

    By the way, my ‘test’ of whether I’m truly hungry isn’t something delicious like steak or lobster–I ask myself whether I want to open a can of tuna. When I realize that I actually want chocolate cake ins tread of tuna, I know it’s ‘head hunger.’ My experience is that after that weight loss, my ‘head’ always wants to eat more than my body needs–and I try to deal entirely with the latter–eating to nourishment of the body and no more. So far it’s working, but it’s a continual challenge.

    • rdfeinman says:

      Congratulations on conquering this problem. Few who haven’t experienced it understand this relation to food and how hard it is to get control. Tuna is an excellent probe for “hunger” as opposed to, as you call it “head hunger”

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