Insulin And Appetite

      78 Comments on Insulin And Appetite

Many of you may recall a kerfuffle raised by a controversial article claiming that we’ve got it all wrong about insulin. Far from being a driver of weight gain, according to the article, insulin is actually an acute appetite suppressant. It makes us less hungry, by gosh, not more.

That article seems to show up on diet-related social media sites on a regular basis. A few weeks ago, some born-to-be-lean jock who joined the Fat Head Facebook group for the sole purpose of being an annoying jackass posted a link to it. I responded, which started a back-and-forth debate.

If insulin is such a fabulous appetite suppressant, I asked, then explain this: type 2 diabetics produce high levels of insulin. They’re also far more likely than other people to be overweight or obese. So why isn’t the acute appetite suppressant causing them to eat less and lose weight?

The response (I’m paraphrasing here): Well, ya see, ya big dummy, type 2 diabetics are insulin resistant by definition. So they don’t experience the effects of the acute appetite suppressant.

Hmmm. Okay, then, explain this one: People will start eating foods that provoke a high insulin response — a big tub of popcorn, or a big bag of chips — swearing to high heaven they’re only going to eat, say, half. Then they eat the whole thing. Then after cursing at themselves for not having any discipline, they go get more. Why isn’t the acute appetite suppressant kicking in and stopping them from eating way more than they intended?

The response (I’m paraphrasing again here): Well, ya see, ya big dummy, the food-reward properties of the popcorn or chips override the appetite-suppressant effect of the insulin.

Ahh, I see. So there’s really no need to adopt a diet that reduces your insulin levels, because insulin is actually an acute appetite suppressant … unless 1) you’re insulin resistant (like so many obese people), or 2) when you reach for high-carb foods, you choose the ones that taste good.

Well, that is fabulous news indeed for all the obese people out there who aren’t insulin resistant and prefer carbohydrate foods with little or no flavor.

I chose not to engage in an endless online debate because I had more important things to do, like write software code for work, take the girls to their piano lessons, and rearrange my shoes by size, color and length of service.

But while digging up some research for the book project, I stumbled across a study abstract that caught my attention because it mentioned something about using insulin to induce weight gain. So I called upon one of my super-secret, deeply embedded, password-protected double-agents in academia to get a copy of the full paper.


It’s the normal rats I’m interested in. Here are some quotes from the paper:

To induce overeating and weight gain in normal rats without brain damage, we used periodic injections of long acting insulin. Measurements of body weight and ad-lib food (powdered Purina chow) and water intake were taken on 23 Sherman female rats, housed at 80 ± 2° F. during a 2-wk. control period, 2 wk. of insulin treatment, and a 2-wk. recovery period. The insulin dose was 8 units per injection for the first 3 days, then 12 units thereafter.

Boy, those researchers must have been disappointed. Here they were, hoping to induce overeating and weight gain, and yet they injected the rats with an acute appetite suppressant. Big mistake, obviously.

All rats given protamine zinc insulin increased their food intake, presumably in response to hypoglycemia. In the short term experiment, 11 of the 23 rats survived by consuming nearly twice their normal daily food intake.

The rats who didn’t survive apparently died because they couldn’t eat enough to keep their little bodies fueled while the insulin drove down their blood sugar and locked up their fat cells. They were eating like crazy, but starving at the cellular level.

That reminds me of the conclusion from another paper in my files: appetite is largely a function of how much fuel is available at the cellular level, not how much fuel is consumed.

Their average weight gain was 58 gm. during the 2 wk. of insulin treatment, as compared to 13 gm. during the previous 2 wk.

This confirms the original observations of Mackay et al. (1940) and extends their results to indicate that marked obesity as well as overeating can be produced with insulin.

So marked obesity and overeating can be produced with injections of the acute appetite suppressant. Got it. Well, perhaps the rats injected with insulin just happened to find that powdered Purina chow waaaay more rewarding all of a sudden. Maybe the researchers added salt.

Every rat taken off the insulin regime after 2 wk. ate subnormal amounts of food and lost weight precipitously. On the average they were anorectic for 4 days, and lost 46 gm., which was 79% of the weight previously gained under the influence of insulin.

Researchers stopped injecting the rats with the acute appetite suppressant, and the rats responded by eating less and losing weight.

Boy, that almost sounds like what happened when I jettisoned a lot of insulin-producing foods from my diet. Reduce circulating levels of that acute appetite suppressant, and I’m just not as hungry.


78 thoughts on “Insulin And Appetite

  1. Barbara

    Wish I could jettison the weight as fast as the rats did. Oh wait, I’ve been following the guidelines for 50+ years. Maybe I am.

    1. Thomas E.


      Same here. As my wife says it took me 30-35 years of eating like an ass to get the body I deserved from such diet. I can’t expect my metabolism and body to fix itself overnight.

      I am currently at my body’s set point when I was power lifting/body building, just without all the extra lean muscle tissue 🙂 Hopefully we will be able to break through our current set points and get to were we want to be.

  2. Eric from Belgium

    If I recall correctly, from research dating back to a couple of years ago, ghrelin is the hunger hormone, produced by the stomach. Drives my cats crazy in the morning…
    Leptin, on the other hand is the satiety hormone, basically signalling your brain that you’ve eaten enough, produced by the fat cells.

    But, according to that research, insulin blocks the message from leptin. So, if I eat sugary stuff, I will keep on eating, as ghrelin is blocked.

    Maybe that’s why if I start eating chocolate, I cannot stop ???


      1. Eric from Belgium

        Yup, it is…

        Had a free package of muesli with chocolate given free with our last supermarket order… It has chocolate in it.. Must resist temptation….
        That stuff is sold as “healthy”, but it’s loaded with sugars….

        Must resist…..

        By the way, belgian beer is even more awesome…..


        1. Cameron Hidalgo

          When my sister was born in a Belgian hospital, back in the late 80s, they gave my mother beer with most meals. Is this still common practice?

          1. Eric from Belgium

            When I lived in MO and told folks that we got beer at school lunches when I was 6 years old, it freaked quite a few people.
            Of course it was not a 9% alcohol beer, it was something called Piedbœuf Blonde, which is about 1% alcohol, and brewed with spent malt.
            It’s still available, although not served in schools anymore. Kids prefer soda nowadays….

            @gallier2: unfortunately very few ‘friteries’ use beef tallow nowadays. Because of the b****it about saturated fats most use vegetable oil, which oxidises very rapidly.


    1. Dave

      I recall in one of Gary Taubes’ books that fat storage was actually higher at the injection points for some diabetics. He had a photo reference for this phenomenon. This would seem to indicate that something more than just appetite is involved in weight gain.

      1. Tom Naughton Post author

        Yeah, the photo was of a guy who injected insulin on both sides of his belly button. Looked like he was growing boobs down there.

        1. Walter Bushell

          Also, Mr. Tabues had photo of people fat below the hips and skinny above, or vice versa or both. Girls gain fat when they hit puberty and boys gain muscle .

          Ah, the pictures were in the lectures not in the books.

          Taubes — Why We Get Fat on Youtube

          About 34 minutes in with cattle and 36 minutes people.

          Caution — shows naked people.

          Anyway his works show hormones rulz.

          1. Craig Rich

            Yep. I’m in school studying to be a nurse. We are trained to tell people to change injection sites when administering insulin or else fatty deposits will form there. This isn’t just something Taubes knows, everyone in the medical establishment should know this: is you inject insulin in the same spot all the time, fat will deposit there. Any textbook will tell you that.

  3. Nads

    I’ve heard that both types of Diabetics can tend to gain weight once on insulin.

    The other thing I have heard though, by proponents of the fructose theory, is that at least the insulin response means the brain registers that the body has received food whereas with fructose it doesn’t.

    1. Tom Naughton Post author

      That’s true. A moderate rise in insulin should, in fact, signal the brain that food has been received. But when insulin stays too high for too long, it’s going to lock up fuel and increase appetite as a result.

      1. Walter Bushell

        Not only *that* but sustained high levels of insulin cause more insulin resistance[1]. This is the reason type II diabetics get wurst with treatment and the treatment makes sausage of their metabolism.

        Every teenage girl on insulin knows that stopping or reducing insulin will result in weight loss and if you tell your doctor that you have been losing weight, the first though is diabetes. I’ve been through the drill a couple of times; it’s automatic, practically a conditioned reflex on the doc’s part.

        Dr. Lustig pounds this point, “I can make anyone fat”.

        I like the end of the list of things that were more important that argufying with that dude, arranging your shoes, comic genius, but color should come near the top of the list —
        white shoes are out ’cause it’s after Labor Day, for example.

        [1] As with most substances. The ACORD studies show that
        tight control of blood sugar makes the situation worst.

        1. Tom Naughton Post author

          Chicago Bears QB Jay Cutler lost 35 pounds during a season some years back — not something a guy facing Clay Matthews and other big-fast-tough linebackers wants. Turns out it was type I diabetes. Insulin therapy helped him put the weight back on.

          I don’t own any white shoes.

  4. BobM

    Dr. Fung has a bunch of studies where people given insulin gain weight — usually a lot of weight. See this article for instance:

    I note that if I decrease my insulin (though low carb, high fat and/or intermittent fasting), I’m much, much less hungry. Meanwhile, when I was eating a low fat diet, I could eat a large bowl of brown rice and beans with salsa (nice and very low fat — note the lack of meat) and be famished 15 minutes later. I used to believe that was mainly caused by high blood sugar, but now I believe it was caused by high insulin level.

    Unfortunately, not everyone reacts to high carb diets as I do. I know several people who eat low fat and have no (ostensible) problems doing so. By contrast, if I eat a high carbohydrate diet, my blood sugar goes through the roof, I get angry, depressed, etc. Whereas eating a low carb diet causes the exact opposite.

    1. Tom Naughton Post author

      “For decades we believed the Caloric Reduction as Primary (CRaP) hypothesis of obesity…”

      LOVE IT!

      Sure, some people can live on high-carb foods, no problem. The rest of us aren’t so lucky.

      1. Mike

        I was just watching a speech by Tim Noakes the other day and I think he more or less said that the ability to do that is part of what gives some elite athletes their superpowers. He said the Kenyan runners can eat 600 grams of carbs. So perhaps it shouldn’t be too surprising if you can’t eat carbs if you don’t have any Olympic medals laying around.

    2. Stephen T.

      Bob, I was considered slim when I was on the low-fat diet, but I often felt tired and my mental resilience decreased as the years went by. I was pretty disciplined and avoided sugar and junk, so I was doing something right and that probably helped me to stay slim.

      I wonder how well slim low-fat people really are? Because they’re not fat, we assume all’s well, but at least for some I doubt that’s correct. Since I went low carb and high fat, I feel much better, both mentally and physically. I also enjoy my food much more.

      1. Walter Bushell

        O yes. There are people who are “skinny fat”. Thin arms and legs and bulging bellies, for example, but by BMI, they are A-OK. BMI is considerably less accurate than just looking at the subject. If someone *needs* a number waistline is a good test, which requires less equipment even.

        BMI was not designed to be applied to individuals, but only to populations of adults. Butt it is applied willy nilly[1] to individuals and children.

        [1] Willy nilly does not mean as I used to think, lacking a penis.

        1. Stephen T.

          Walter, half the England rugby team are obese according to BMI. Rugby is the game where big men hit each other hard but don’t wear padding and helmets.

      1. Dianne

        PS — speaking of idiotic arguments, did you get my email re the study about the supposed calming effects of sugar vs. aspartame on the brain?

          1. Dianne

            I know sugar affects the pleasure center of the brain (didn’t even need an MRI to tell me that one!) but what got me about that “study” was that instead of having the women whose drinks were not sweetened with sugar drink something neutral like water, they had them drink stuff sweetened with aspartame, known to cause neurological problems in some people. As I mentioned earlier, I had to stop using aspartame because it made my fingers, toes and lips go numb, and made me have trouble swallowing. My husband gave up aspartame because it made the muscles in his arms twitch and jump. A lady I knew some years ago had to quit using it because her doctor figured out it was the cause of her agonizing headaches — which didn’t go away completely until a year after she stopped using aspartame. So the question is, did the sugar in one group’s drinks have a calming effect on the brain, or did the aspartame the other group drank produce stress hormones? Or was it some of both?

            1. Jennifer Snow

              Huh, I didn’t know this was one of the effects of aspartame. I wonder if that’s what causes (or contributes) to my left eye twitching. Pepsi recently took aspartame out of diet Pepsi, btw.

              I also recently found out that caramel color (found in all colas) has gluten in it because it’s made from barley. 😛

            2. Tom Naughton Post author

              It only seems to have that effect on some people. My mom’s doctor told her he’s noticed way more women experiencing the numbness effect than men.

            3. Dianne

              But we’re allowed to feed it to children whose brains are still developing. Those same children whose developing brains are not permitted to have saturated fat in school. Sheeeeeeeeesh!

  5. fredt

    “insulin is actually an acute appetite suppressant” — is that from the paper where the researchers injected insulin directly into their tiny brains?

    The ambiguous wording is intentional.

  6. Beats93

    Hey Tom,

    Was there a post this summer about you and Jimmy’s annual disc golf tourney, or did I miss the post? I’d love to see who won 😛


    1. Tom Naughton Post author

      I didn’t post about it, other than to mention when he and Christine were here.

      First couple of days I was winning nearly every round. Then I finally (after two years of trying) talked Jimmy into accepting a handicap system. I understand the desire to compete straight up. It’s a guy thing. But I play my course at least 100 times per year, while he plays it one week per year. I have an unfair advantage. In addition to knowing every angle on the course, I’ve developed a longer drive by virtue of playing so often.

      So the three par 4s became par 3s for me, and the longest par 3 became a par 4 for Jimmy. After that, he started playing me pretty even, which is what I wanted. It’s way more fun out there if he stands an equal chance of winning each round.

    1. Tom Naughton Post author

      “When it comes to the nutrients dogs need, grains deliver.”

      Heh-heh … I guess that’s why wolves are always invading the wheat fields and chowing down.

      1. Firebird

        When are you going to post photos and blog about the fence you need to build to keep the foxes from invading your carrot garden?

      2. Arturo Silva

        Does that mean we should sue all the grain-free dog food manufacturers for false advertising since it’s been known ALL ALONG that… grains have what dogs need?

        Also, I’m getting another Brawndo flashback with this.

      3. Mike

        As I understand it, we’ve had dogs longer than agriculture, and we’ve taken our loyal friends down the carb road with us.

        Dogs are ominvores, but I do wonder what that means in practice. How many berries do wolves manage to eat? I’ve never met a dog that didn’t like carrots, but I’ve never set a dog loose in a carrot patch to see what he would do.

        Our dogs have a demonstrated ability to harvest cucumbers that grow through the fence keeping them out of the garden. They eat a good chunk of one, but leave enough that we know what happened. The do this when we aren’t around, so it isn’t a case of wanting to eat whatever the human has.

        Ours really like broccoli stems too, but not the florets.

        1. Tom Naughton Post author

          Dogs are omnivores, and they’ll eat almost anything you put in front of them — like a lot of humans. But feed dogs grains, and a lot of them will become fat and sick in short order.

    2. Elenor

      I reacted for horror (and I think I sent you the article, Tom) when, a couple years ago, the ASPCA magazine actually printed an article about how to “switch your dog to eating vegetarian.” (!!)

      They even printed it in a book! “ASPCA Complete Dog Care Manual” by Bruce Fogle!

      Apparently lots of veggie-warriors have taken over the ASPCA. I switched my donations to animal rescue organization NOT including ASPCA!

    3. Thomas E.

      Experiments, since we all seem to experiment with ourselves, my wife and I decided to do some with our pets. My wife now goes to great lengths to find the most natural meat filled, least carb filled pet food we can afford. Basically, yeah, we did a little research and found, dogs and cats are carnivores, go figure.

      And guess what, all 3 cats lost weight, and the oldest who was starting to have a hard time with the stairs and jumping on our bed, no problems now. And the dog is thriving.

      Go figure. 😀

  7. Galina L.

    Usually insulin is used to increased appetite (for anorexics) not to reduce ; as far as I know, no one is using it to suppress appetite. Here is another rut study – insulin is administered to overcome a chemo-induced anorexia. Diabulemia is a well-known eating disorder among insulin-dependent diabetics.
    While reading nutritional blogs, one could find many examples that some study(s) could be used in attempts to denounce well-known facts. It is done in writing only (not in practice) by some people for personal reasons, but such exercises have only amusement value for those who enjoy that type of entertainment.

    1. Tom Naughton Post author

      I also dug up some studies in which insulin treatments caused humans to gain weight. Maybe I’ll cite those in another post.

    1. Tom Naughton Post author

      Well, OF COURSE it happened … then that darned cat got into my closet and pushed the shoes every which way.

  8. Superchunk

    People interested in this may want to check out Peter’s post at Hyperlipid from 8 or 10 months ago about this topic. (I tried to find it but couldn’t on short notice). The summary is:
    – Apparently the idea that insulin suppresses appetite was primarily originating from a “researcher” in Cincinnati.
    – A drug company wanted to create a drug based on this idea to suppress appetite, but they could not replicate the finding in their lab
    – They had the researcher try to replicate the finding, but again, no luck.
    Conclusion, don’t put too much reliance on findings that haven’t been validated by a number of independent people in different settings. Common sense conclusion: Even if insulin does suppress appetite in some lab setting, it must be a very weak affect or one which is overridden by some other mechanism as described above.

    1. Tom Naughton Post author

      If tasty chips or popcorn can override the “acute appetite suppressant,” it’s not much of a suppressant.

      1. Jennifer Snow

        It’s been my experience with non-carby foods, even those with exceptionally high food reward (like, you know, BACON, which is probably the yummiest food in existence), that when I’m full, I’m FULL and no amount of food reward is enough to overcome it. In fact, I’ll feel slightly nauseated at the thought of consuming any more food even though I know purely volume-wise that I could cram more in there. I can eat carby food until my stomach is painfully distended and not feel “full”. Half a plate of bacon and eggs and I’m like “UGH SO MUCH FOOD”.

        1. Tom Naughton Post author

          I don’t completely discount the food-reward idea. After all, food scientists are paid a lot of money to create “bet ya can’t eat just one” snacks. The right flavors probably do make refined carbs hard to resist. But as you pointed out, nothing seems to make people gorge on bacon … or eggs, or steak.

          1. samc

            ” But as you pointed out, nothing seems to make people gorge on bacon … or eggs, or steak.”

            I surely can if I don’t exert some self control. Theory busted.

            1. Jennifer Snow

              Maybe, although I bet if you tracked what you ate you’d be surprised at how little you were taking in compared to the amount of calories a carby gorge can be.

              I’ve done this myself and thought “man, I musta eaten like 5000 calories there” and it turned out to be less than a third of that. So I just let the full signal do its job when I’m eating that stuff.

          2. Jennifer Snow

            I have a suspicion that the “food reward” of this stuff is from the fact that it leaves your mouth feeling nasty after you eat it, so you want to put another piece of food in your mouth to get rid of that nasty feeling. I’ve noticed this A LOT with “can’t eat just one” foods. It’s not so much about how the food itself tastes but what your mouth feels like after you finish eating it.

            If you wanna test it, try eating a handful of some snack then wait 5 minutes and see how your mouth feels.

            1. Tom Naughton Post author

              I’m not a food scientist, but my guess is that they gear this stuff to produce a dopamine hit.

            2. Craig Rich

              It’s not that hard. I recently observed a circumcision in a baby. What do they use to numb the pain? Sugar. They put a few drops of glucose (or sucrose, not sure) on a pacifier/nipple and the baby doesn’t cry much or long during the circumcision. Sugar is a powerful drug against pain and exciting the pleasure centers of the brain.

  9. T33CH

    I commented on Stephen Guyanet’s article regarding Dr. Hall’s stunning study that showed low fat beating low carb hands down.

    I asked him why, as he mentioned in an very old post, Americans are consuming over 100lbs of sugar a year today compared to 13lbs in the 1800s especially if it was super satiating from all of the extra insulin. Why don’t we see this same trend with fat or protein if it so satiating? Hmmmmm….

    1. Mike

      As Tom points out in Fathead, when you are full of sugar, your body does various things to get rid of it ASAP, including turning off fat burning until the sugar is gone.

      It seems perfectly reasonable to me that suppressing appetite could be part of that, and then when sugar tanks, you chow down on more. Does the “can’t eat just one” phenomenon work just as well on people who aren’t insulin resistant as those who are. Maybe there is some appetite suppression mechanism, but it’s broken in a lot of us.

  10. Nate

    From the American Diabetes Associations website one sign of hypoglycemia is hunger. (Hypoglycemia means low blood sugars and thus relatively high insulin levels.) In fact, all guidelines for dealing with low blood sugars for insulin dependent diabetics list hunger as a sign of low blood sugar. For me, hunger is by far the most common sign my insulin is starting to take me for an unpleasant ride.

  11. William Norman

    The born-to-be-lean jock has moved his annoying jackass posts over to Richard Feinman’s group, but it’s nice to be free of him in the FAT HEAD group.

  12. Ben Green

    Dr. Lustig’s research already demonstrated that insulin blocks the brain from receiving the leptin signal at the hypothalmus. No leptin signal=increased appetite, decreased spontaneous physical activity/NEAT/fidgeting.


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