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Why The Insulin-Obesity Hypothesis is Iffier Than You Think

insulin leptinI have personally never bought into overly simplistic notions of what may or may not cause obesity (or what we can do about it).

One of these “simplistic” notions that has gained considerable traction recently is the idea that insulin resistance (caused by over-consumption of high-sugar/high-glycemic foods) leads to “internal starvation” and provides a (calorie-independent) stimulus for weight gain.

While this hypothesis has garnered much recent popularity due to enthusiastic and outspoken supporters like Dr. David Ludwig (Always Hungry?) and Gary Taubes (Why We Get Fat), the basic idea is neither new nor unchallenged.

While insulin may well be involved in the “non-caloric” regulation of body weight – there are numerous bits and pieces of the hypothesis (as popularly presented by Ludwig and Taubes) that are inconsistent and not backed by hard observational and/or experimental data.

For an enlightening read on why the insulin-hypothesis of obesity may not be all that accurate, readers may wish to read an elegant discussion of this issue by Dr. Stephan Guyenet, a neuroscientist at the University of Washington, and author of Whole Health Source, a popular health blog.

Without going through all the pros and cons of the insulin argument here (these are eloquently discussed by Guyenet on his site), allow me to quote his summary,

“In summary, several key predictions of the insulin model are not supported by the evidence, explaining why this model doesn’t get much traction in my field (neuroscience).  There is essentially no direct evidence that the proposed mechanism occurs during or after normal weight gain, a fair amount of direct evidence that it doesn’t, and the arguments in favor of it are based on indirect evidence whose relevance to common obesity is often questionable.”

While I have no stake in this discussion either way, I generally remain sceptical of overly simplistic explanations for complex biological phenomena. Guyenet’s arguments are anything but simplistic.

Edmonton, AB


  1. Until the medical profession recognizes obesity as a group of separate conditions, and provides antidotes to each separate condition, obesity cannot be beaten down. Sorry to those who find this offensive and I feel pity for those who consider this wrong.

    Insulin overshot only occurs when overeating on good tasting carbohydrates and only for some people. Those people are usually a self selecting group of severely obese, if they did not have this condition, they would not be as obese. Once they learn this, they become among the partly ex-obese. Those that suffer get relief from no/little carbohydrates. For the first few days there are considerable physical craving for the plentiful carbohydrate. After that they head for a new “set point”, as long as they stay off carbohydrates, but may also have additional overeating problems.

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  2. Thanks for the mention, Dr. Sharma! One minor correction: I’m no longer at the UW. I’m currently writing a book full time. Cheers.

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  3. Insulin is a catabolic hormone, so increased insulin (due to insulin resistance) can cause carb cravings, accumulation of fat in the abdominal area, which can then cause more insulin resistance.

    I don’t believe insulin resistance is caused by overconsumption of high fat/high carb meals. The cause of insulin resistance is quite complex and the treatment is as complex!

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  4. La teoria de la insulina es mucho mas compleja que la teoria del balance energetico
    Efectivamente INSULINA es un factor, LEPTINA, hipotalamo y corteza cerebral, entre otros
    Sin dejar de lado sueño, luz y ambiente socio cultural
    Pero excepto los ultraprocesados, el resto existio siempre y la obesidad auemnta

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  5. This presentation by Stephen Guyenet is worth watching. Note what he says about linoleic acid, the most pronounced dietary change of the 20th century and beyond.

    And this blog post by Michael Eades points the finger at linoleic acid, arguably the most potent component in the food supply in terms of appetite derangement.

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  6. I’ve been hoping you would say something about this. I was excited about Dr. Ludwig’s book because I knew he was a respected endocrinologist, but then when I read it and started coming across terms like “retrain your fat cells” (without a clear scientific explanation of how exactly that works), saw that it was full of testimonials from people whose results were from what amounted to a 20-week diet plan, saw recipes for drinks made with protein powder, etc. etc., I was really disappointed. Alas, essentially another diet book.

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  7. Bravo! The insulin hypothesis has every virtue save one: truth. Low carbohydrate diets ‘work’ because they are low calorie diets. Ketosis causes diuresis adding to the illusion of efficacy. But it’s all smoke and mirrors.
    The truth is that obesity is very complex. Chronic inflammation certainly plays a role but so do many other factors including, of course, genetics, culture, age and lifestyle.
    Ketogenic diets sell books. They are otherwise rather silly.

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  8. I can’t claim to have an absolute scientific explanation, much less one that applies to everyone. But I can speak from personal experience. I strictly cut down on carbs and sugar while, if anything, increasing overall fat and calorie intake. What was the result? I lost 60 pounds, even though I was exercising no more than before.

    The only way I can understand this is the extremely low levels of carbs and sugar that put me into ketosis and that in turn eliminated my cravings for carbs and sugar. It was amazing to me that I could lose years of accumulated fat by eating large meals. Only after the fat loss did I start doing intermittent fasting and restriction of eating time, as a way of maintaining my present state.

    For damn sure, a calorie isn’t a calorie isn’t a calorie. Carbs and sugar have an impact on my body in a way no other category of food does. I’ve never been diagnosed with diabetes and, besides depression, have always had high levels of health. I get sick at most every few years. The only thing that motivated me toward dietary change was weight gain that wouldn’t go away no matter how much I exercised.

    I’m not sure what that all adds up to. And I don’t know how it applies to anyone else. I just know what worked.

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