Study finds those eating low-fat diets with high insulin levels are most prone to weight gain

It’s difficult to avoid the doom-laden statistics concerning rates of overweight and obesity. And at the same time we’ll no doubt be aware of the standard advice for those wanting to lose weight: ‘eat less and exercise more.’ The problem is, the evidence suggests that neither of these approaches is particularly effective for the purposes of weight loss in the long term.

Some researchers and scientists are in the process of thinking a little more creatively about the ‘obesity epidemic’. What, some are asking, if weight is not determined simply by the relative amounts of calories taken in and those that are metabolised by the body?

One important factor here concerns appetite. It makes sense for individuals who want to curb any tendency to overeat to consume foods that tend to be appetite-sating relative to other foods. The usual advice is geared toward getting individuals to eat a fibre-rich diet because, supposedly, ‘fibre fills us up’ and helps us ‘feel full for longer’. Actually, there is good evidence that, overall, protein is the part of the diet that packs really appetite-sating power.

Another factor well worth considering concerns the tendency for food to predispose to fatty accumulation in the body. While it seems obvious that the major dietary spectre in this respect is fat, the reality is that the prime fat-producing hormone in the body is insulin. And insulin, as we know, is secreted chiefly in response to intake or carbohydrate.

Some have theorised that weight gain can be driven by a glut of insulin. Perhaps the most famous/infamous person to put forward this theory was the late Dr Robert Atkins. Others have come in his wake. Recently, new life has been breathed into this concept by Gary Taubes, author of ‘Good Calories Bad Calories: Challenging the conventional wisdom on diet, weight control, and disease’. I’ve not read this book, but know enough about it and Taubes’ previous work to recommend it to anyone who takes a keen interest in their (or other people’s) health.

While weight gain is unlikely to be solely about insulin, my belief is that it is likely a major factor here. Some support for this has come from a study published this month in the American Journal of Clinical Nutrition [1]. The researchers in this study basically assessed insulin levels (actually insulin levels 30 minutes after giving individuals 75 g of glucose) in 276 people and then followed them for an average of 6 years each. This insulin measurement can be taken as a proxy measure of an individual’s ability to handle carbohydrate (sugar) in the system.

The authors looked at the relationship between insulin levels and certain measurements including weight gain and waist circumference. They also, analysed whether there was any difference in results in those eating a low-fat diet compared to those eating a higher fat diet.

Here, essentially, is what they found:

In individuals eating a lower fat diet, higher levels of insulin were associated with an increased risk of weight gain and increase in waist circumference.

This association was not evident in individuals eating a higher-fat diet.

Overall, in the low-fat eating group, individuals with the highest insulin levels gained 4.5 kg (9.9 pounds) more than those with low insulin levels.

So, what are we to make of all of this? The most obvious thing to come out of this study is that higher insulin levels are associated with increased tendency to gain weight. This finding clearly lends support to the idea that insulin may have a key role to play in weight gain.

But why would this association be only evident in those eating a lower-fat diet? I don’t know for sure, but it’s likely to do less with fat, and more to do with carbohydrate: Because high insulin levels are generally a sign that individuals are not coping well with carbohydrate in the body, one might imagine that eating a carb-rich diet is more likely to land these people in trouble than those eating a lower carb diet. Those eating a low-fat diet tend to eat a diet rich in carb, and this may explain why these individuals were the ones most prone to weight gain.

Of course the corollary here is that individuals eating a higher-fat, and therefore lower carb, diet are likely to be less prone to weight gain induced by insulin, right? This finding doesn’t prove anything. But it does sure seem to lend some support to the concept of carbohydrate-control for weight loss.


1. Chaput JP, et al. A novel interaction between dietary composition and insulin secretion: effects on weight gain in the Quebec Family Study. Am J Clin Nutr 2008;87:303-309

15 Responses to Study finds those eating low-fat diets with high insulin levels are most prone to weight gain

  1. Chris 20 February 2008 at 11:40 am #

    With reference to Taubes. Good Calories….is a great (great as in “big” as well as “very good”) book, (released under a different title in the UK for some reason). Taubes goes over the key points of his argument in a very good and entertaining lecture that is available on Google Video or via my site:

  2. Dr John Briffa 20 February 2008 at 11:56 am #

    Thanks Chris
    I think the choice of book title in the UK: ‘The Diet Delusion: challenging…’ is an attempt by the publisher to mimic/ride on the back of Richard Dawkins’ ‘The God Delusion’, but I may have this wrong.

  3. Anna 20 February 2008 at 5:03 pm #

    Taubes’ book is excellent, and by far the most comprehensive book currently out there on this subject. I highly recommend it, though many, if not most non-medical people will find it quite dense and perhaps a bit off-putting in the sheer amount of biochemical detail. But I think the effort to get through it and understand it is well worth it.

    Additionally, Taubes give an excellent and thorough history of nutrition science and how we got to where we are today, with a half century of misbegotten science condemming saturated fat and cholesterol and elevating carboydrates. The low fat camp seems to have a rather short historical perspective.

  4. Chris Highcock 20 February 2008 at 6:58 pm #

    Dr John

    I spotted this study that was just published indicating several benefits to a low carb diet and particular benefits if that diet includes eggs:

  5. Neil 20 February 2008 at 9:46 pm #

    ” I think the choice of book title in the UK: ‘The Diet Delusion: challenging…’ is an attempt by the publisher to mimic/ride on the back of Richard Dawkins’ ‘The God Delusion’, but I may have this wrong. ”

    Hadn’t thought of that, mind you, I thought it was just a better title than GCBC!!

    Currently just getting to the end of the first 200 pages, very stimulating. So far though Gary Taubes seems to believe that the smaller LDL particles can somehow penetrate the endothelium. Personally, I think Malcolm Kendrick’s explanation of plaque formation passes the test of Occam’s razor in a more convincing fashion

  6. Marilyn Leahy 20 February 2008 at 10:36 pm #

    I think you will find better ground for your speculations by reading at least the relevant sections of Taubes book. He discusses the research on insulin and fat accumulation in exhaustive detail. In fact, I think anyone who comments publicly on insulin and fat should address Taubes’ view of the evidence.

    Taubes has provided us with the only theoretical framework that makes sense of 150 years of data. Taubes has written the unified field theory of obesity and the diseases of civilization. Please do yourself a favor and read GCBC as soon as possible.

  7. Anne 21 February 2008 at 10:27 am #


    I read that article on low carbohydrate diets and eggs with interest as I like eggs and am on a low carbohydrate diet….but then I read on page 18 “The authors wish to thank the Egg Nutrition Center for funding this study”. I would hope the study wasn’t biased but I would guess it must be unless I’m overly cynical.


    Chris Highcock wrote:
    I spotted this study that was just published indicating several benefits to a low carb diet and particular benefits if that diet includes eggs:

  8. Sally 22 February 2008 at 5:14 pm #

    Just a brief personal story to endorse the low-carb way of life (after all, not all evidence is empirical): About 5 years ago, I was diagnosed as being significantly hypothyroid. I had gained a lot of weight, in spite of regular aerobic exercise and what I thought was a healthy diet. I really struggled to lose the weight, even when my thyroid levels were restored to normal limits. Between wathcing my diet and exercising hard, I was eating a net 900 to 1,000 calories a day and it was all I could do not to gain weight. My endocrinologist sent me for a 3-hour glucose tolerance test, at the end of which my blood sugar registered 52! The doctor thought I might have hyperinsulinemia since I had always had to work hard to keep my weight down. She suggested various tests but wanted me to try a low-carb diet before we did anything – sensible woman.
    I followed her advice and lost 10 pounds a month for 3 months! It was so easy, and in addition to getting down to 136 pounds while eating more than I have ever eaten, I also lost that horrible mid-afternoon ‘slump’ in energy.
    I really keep an eye on my carbs and eat what the ‘politically-correct’ nutritionists would consider a diet too high in protein and moderatly high in fat (scrambled eggs for breakfast practically daily!) yet I have maintained the weight loss, and my triglycerides, LDL, and HDL etc, are perfect. I occasionally have my blood sugar tested and it is now very stable. Having reaped the benefits, I know I will never go back to my old way of eating, even though I thought it was healthy at the time and is still promoted as such by the mainstream dieticians.

  9. Chris Highcock 22 February 2008 at 7:16 pm #

    Anne – thanks for spotting that! That adds to my general cynicism!

  10. Carol Homer 23 February 2008 at 4:00 pm #


    as a hypothyroidic person and not being able to lose weight easily – tell me did you stop eating much fruit too? I have high levels of HDL and am told by my doctor this is good as the Amish have this too and live a very long life! Hoping this is the case.

  11. Hilda 23 February 2008 at 4:56 pm #

    SAlly. It is not nutritionists who are ‘ploitically correct ‘ in that they do not recommend the diet you are on. It is the dieticians. I am a nutritionist who would endorse what you are saying as would many other nutritionists. Hilda

  12. Neil 24 February 2008 at 6:49 pm #

    the ideal as i have read, is high HDL, low Triglycerides. This combination should also alter the profile of the various LDL particles favourably, LDL possibly being of lesser concern than HDL or TGs.

    A low carbohydrate appears to be the way to achieve this. A lot of fruit would certainly raise your carbohydrate intake, depending on which fruit and in what quantity

  13. Sally 25 February 2008 at 1:04 pm #

    Yes, I did cut back on fruit and also on high glycemic vegetables, although I eat carrots and varieties of squash now and again. Generally speaking, I rely mostly on vegetables for my carbs since they are also a good source of fiber. For fruits, I really love apples but limit those to no more than 1 a day. I also enjoy berries (espcially with a splash of cream!) since they tend to be lower GI fruits (again, not something I would eat daily but really to add some dietary variety – and as a dessert-type treat).
    In my nursing school days, we were taught that the ‘H’ in HDL stood for ‘happy’ while the ‘L’ in LDL stood for ‘lousy’ – perhaps a bit silly, especially considering what Dr Briffa says about the lack of published data on what really constitutes healthy and unhealthy levels of each, but it helps to distinguish which is which. I have also heard that regular excerise even of a moderate kind helps to raise HDL.

    Hilda: Apologies for the error, and thanks for pointing that out.

  14. Curtis 21 July 2008 at 11:36 pm #

    This is why it’s so good to tailor the diet to the individual. My work is in helping obese children learn better eating habits.

  15. TONYA 13 October 2009 at 11:09 pm #


Leave a Reply