Study demonstrates the key role insulin plays in obesity

Our experience of health and disease will always be the result of an interplay between our genes and ‘environmental’ factors such as diet, exercise and exposure to potential toxins or health hazards. We hear a lot about the role of specific genes in specific conditions such as diabetes and heart disease. However, as Professor Steve Jones ” professor of genetics at University College London in the UK ” recently pointed out in a newspaper article, gene identification has not really got us very far in terms of understanding the mechanisms behind disease and how best to prevent and treat them.

Also, we know that there as been a relative explosion of certain chronic conditions, including obesity and type 2 diabetes, in just the last few decades. Assuming that our genetic make-up s a species has changed very little in this blinking of an eye, then really and truly, it is likely that it’s changes in environmental factors that has led to the steep rise in the rates of these health issues: Genes may load the gun, but it’s environment that is largely responsible for pulling the trigger.

Recently, I came across an article on the website Science Daily that was entitled ‘Factors other than genes could cause obesity, insulin study shows’. Fortunately, I don’t always let article titles that appear to be stating the obvious put me off actually reading them. This article is interesting in that it talks about a study which attempted to see what it is about fat cells that seems to lead to some storing more fat than others. The relevance of this is that obesity may be regarded as a condition of excessive fat storage. So, if we understand the mechanisms behind this, we might be in a better position to do something about it.

Now, a lot of people in the nutritional field believe that they know what causes people to be overweight: eating too much and/or not exercising enough. This view is based on the calorie principle that basically maintains that if we eat more calories than we burn we will gain weight, but we’ll lose weight if we consume fewer calories than is burned in the body.

While this makes sense, it is also somewhat simplistic. For example, if calorie consumption is reduced, energy expenditure tends to reduce too (reducing calories can put a dent in the metabolic rate). And exercising more can, ultimately, result in the body compensating with an increase in food intake (as a result of increased hunger). These mechanisms help explain why both calorie-reduced diets and aerobic exercise have been found to be generally useless for the purposes of weight loss.

The idea that obesity is a disorder of fatty accumulation (and not just down to the calorie principle) is explored in Gary Taubes’ book The Diet Delusion (titled Good Calories, Bad Calories in the USA). In this book, Taubes’ exposes the fallaciousness of the calorie principle, and instead goes after what might cause fatty accumulation in the body.

Now, fat is stored in fat cells as substances called triglycerides. Triglyceride is made from substances known as free fatty acids. It takes 3 fatty acids and one molecule of a substance known as glycerol to make triglyceride. The free fatty acids are absorbed from the bloodstream into the fat cells. They can flow out again too. What ‘fixes’ them in the fat cells is their conversion to triglycerides.

The conversion of free fatty acids to triglyceride is dependent on the supply of a substance called alpha glycerol phosphate. This is produced when glucose is metabolised in the cell. In other words, the more glucose that gets into the fat cells, the more fat will tend to get fixed there.

For most people glucose comes from sugars and starches (carbohydrates) in the diet. But to get into the cells it requires the action of the hormone insulin. So, dietary carbohydrate supplies the glucose necessary for the manufacture of triglycerides, and also stimulate the secretion of insulin which gets the sugar into the cells. Insulin also stimulates triglyceride formation through its action on other hormones (lipoprotein lipase, glycerol phosphate acyltransferase and hormone sensitive lipase).

In short, what this means is that carbohydrate and insulin will tend to cause the accumulation of fat in the cells.

What’s this got to do with the Science Daily article I mentioned earlier? Well, in this study researchers determined genetically identical fat cells were found to have widely differing propensity to accumulate fat. The difference was found to be related to the rate at which cells process insulin: the faster the processing, the more the cells tended to accumulate fat.

This finding is predictable from an understanding of the critical role that insulin plays in fatty accumulation. It should also serve to remind us that the form that calories (not just the number of calories) can affect our propensity to lose or gain weight. And finally, there is good evidence that fatty accumulation is stimulated by the consumption of carbohydrates, particularly those that tend to cause considerable and/or sustained rises in blood sugar. For many, weight loss will come about by simply lowering insulin levels in the body. And the obvious way to achieve this end is to eat less carb.

12 Responses to Study demonstrates the key role insulin plays in obesity

  1. Paul Anderson 7 May 2009 at 4:10 pm #

    I would like to bounce this idea around as an observation and maybe for comment.

    Its been my obervation that the human body is not wasteful, and tends to be geared towards storing food for furure use.

    Once someone has gained weight its relatively difficult to lose weight,and particularly to sutain that weight loss over a period of time. For some this is true no matter how low their carbohydrate consumption: for others they reach a point where further weight loss is almost impossible even though they may remain moderately overweight. Is it possible that the accumulated pool of triglycerides provides a partial source of new fats, even as it is being broken down to be used as a source of energy? Perhaps this is where intermittent fasting can help, by slowly reducing the potential pool of triglycerides. Hence once you gain weight, the body is primed for fat retention/further weight gain. Add to this the fat that circulating insulin levels tend to be proportionate to body fat levels: you have 2 of the essential ingredients for weight gain readily available. Maybe some form of ketosis, elimating some of the glycerol and triglycerides from the circiulating pool, is necessary to restore leanness and insulin sensitivity. In extreme cases there may be a need to carefully monitor protein intake to further limit insulin release and increase insulin sensitivity.

    I think its a shame that in the Uk at least, there is very little measurement of fasting inulin levels, which forces reliance upon proxy measures such as HDL, triglycerides, etc, and liver enzymes.

    My personal observation has been that appetite is also a useful barometer of insulin levels. Lower levels seem to correlate with a much reduced appetite.

    Paul Anderson.
    Paul Anderson.

  2. fluffy_ferret 7 May 2009 at 5:48 pm #

    I would say that our appetite control gets set out of balance by todays refined carbohydrate foods. Insulin and huge glucose loads play its part i’m sure. There are other factors such as a high carbohydrate diet probably being lower in protein, and thus not as satisfying. Energi in-out still applies. You don’t get fet unless there’s a surplus of energy. Carbs are not evil. You can eat non-refined carbs and stay healthy and slim.

  3. Dr John Briffa 8 May 2009 at 2:56 pm #


    Would you know of a good resource for anyone looking to find out more about intermittent fasting?

  4. Kevin eakins 8 May 2009 at 4:36 pm #

    I’d like to address the issue of the “missing” calories and make a few other related observations. A number of writers and nutritionists have questioned the “calories in = calorie out + calorie stored” equation. As you say it makes sense but if different diets that deliver the same calories cause very different levels of weight gain or loss then there is a part of the picture that we are missing. I don’t think its a case of rewriting the laws of thermodynamics so where are the “missing” calories? Here’s my suggestion: when we eat a “healthy” diet we foster the growth of beneficial bacteria in the gut. The energy these bacteria expend energy in multiplying at a faster rate and this accounts for much of the weight loss experienced when dieters replace simple carbs and starches with foods such as fibrous vegetables and healthy protein. The “missing” calories are then simply shed through the formation of faeces on a daily basis. The trouble with this theory is the fact that the Atkins diet causes a rapid weight loss as well but avoids foods which feed the beneficial bacteria. Perhaps the time frame is an important perspective here – short term this diet works but long term it fails. In order to be sustainable a diet has to fulfil all our needs (which by the way drastic calorie restriction clearly does not). The Aktins diet may help help an individual to lose weight rapidly in the short term by replacing carbs with protein and fats as a source of cellular fuel but ultimately its acidity is too toxic for the body to sustain. Alkaline, fibrous vegetables on the other hand take longer than sugar and starch to digest and as they are broken down supply fuel to the gut flora. By symbiotically feeding us and our more numerous “friends” the paleolithic diet kills two birds with one stone. We get fed through proper digestion and feel full and the GIT workers also get their rations which enable them to do the job we need them to do. I think there are many communication channels yet to be discovered between these bacteria and our body. I can not prove it but I’m willing to bet that this two way communication helps us to process the nutrients better and to feel full when it’s appropriate. This would fit in with the perspective of the body as a complex ecosystem system where everything is in interaction simultaneously. I am tempted to suggest that it would not be outrageous to think of the GIT flora as the “extra” organ that plays a critical role in digestion, healthy immunity, and elimination. Missing this “organ” is associated with many problems: eczema, allergies, asthma, auto-immune disease, infant colic, IBS, obesity(?) etc.. etc..
    Could our obsessive characterisation of bacteria as “bad” be a large part of the epidemic of chronic disease problems we face today. As in all things to do with health it seems that healthy habits have multiple benefits and so simple lifesytle measures which are preventive for one chronic disease are generally preventative for all the others as well.

  5. Chris 8 May 2009 at 7:08 pm #

    Kevin, I think you are bang on to bring the gut flora into the debate. The modern diet as is for many must surely be lacking in probiotics from green-leafy sources. I was party to something recently expounding on the importance of gut flora and suggesting that the gut can ‘communicate’ with the rest of the body. I am inclined to want to wise up on this. If I can find a useful work on this I’ll post it to this thread. Likewise in return?
    Neil Shubin ‘Your Inner Fish’ looks to be a readable account postulating that the legacy of 375 million years of evolution from fish to modern man is all too apparent in our physiology.
    On page 187 he writes about decreasing levels of activity in us humans.
    “Our history from fish in no way prepared us for this regimen. This collision between present and past has its’ signature in many of the ailments of modern life
    What are the leading causes of death in humans? Four of the top ten causes – heart disease, diabetes, obesity, and stroke – have some sort of genetic basis and, likely, a historical one. Much of the difficulty is almost certainly due to our having a body built for an active animal but the lifestyle of a spud.”

    Thanks Neil, that’s the evolutionary precedent and lifestyle factors sorted ..

    I agree about our friendly bacteria, they are an order of nature without which the complexification of life would not have been possible. No life would be possible. Who are responsible for the worlds topsoil? Friendly bacteria. Everything lived as part of one big carbon cycle until we took up agriculture. Human activity then began to exploit energy reserves captured by the sun as ‘sunk’ biomass (humus) in the soil. We come along on the take, as has been the recent pattern, grow our food, but put nothing back. We end up with sterile soil that would not yield anything unless we add NPK chemical fertilisers.
    Starved of essential micronutrients the poor plant cannot manufacture the essential polyphenols with which it can defend itself. So we have to spray it with pesticides and fungicides etc. Said poor plant is deficient in polyphenols which through a process of evoloutionary precedent belong to a group we call ‘phytonutrients’ and are important to us too. The pesticides on the other hand are toxic and residues in food are slowly degrading us.

    The irony is that most of us humans think we are smart.

  6. Grant 9 May 2009 at 3:56 pm #

    As a reply to Kevin above:

    The reason you need more calories on a high fat diet vs high carb diet is one of entropy.
    The second law of thermodynamics states that for every reaction there is a loss of energy to the universe. A good analogy is the fuel in your car – only about 12-15% of the power from the fuel actually gets transferred to the wheels.
    In your body the breakdown of starches/sugars to glucose involves minimal reactions so not much energy is lost to entropy. Now if you must produce energy from ketones or protein the list of reactions involved is greater so logically more energy is lost to the system. THAT explains the metabolic advantage of a high fat diet – simple science!

    In a previous study it was shown that women on a high fat vs high carb diet produced roughly twice the body heat over x-period of time – energy lost to the system through heat 🙂

  7. Paul Anderson 13 May 2009 at 2:45 am #


    Apologies for not having replied earlier, but I was away at the weekend at a fitness “fiesta”, and only briefly logged on yesterday.

    The best resource I have come across on intermittent fasting is, an American site.. This site combines various approaches , in addition to intermittent fasting, such as paleolithic type diets, CrossFit, and even touches upon things such as yoga, meditation, etc. It well worth a look and the approach is open and flexible – certainly not a one size fits all approach.

    My own hunch is that the site will become a premium service at some stage, once it is fully up and running, but at present its free and a very good resource, in my opinion.

    Exercise wise it favours weights, bodyweight exercises and inteval type aerobics with the emphasis very much on quality rather than quantity which is also pretty much the theme for the diet/ nutrition appraoch.

    I quite like the blog animal pharm, which is quirky, and quite technical, I guess. It has more of a warrior diet/lifestyle approach.

    As with many of these sites/blogs the interested reader can often learn more by following the discussions/links in the comments section – and of course go off on many a tangent.


  8. Trinkwasser 13 May 2009 at 5:16 am #

    Some fascinating stuff here!

    The original paper is here

    but will require significantly more coffee to digest.

    There’s a prolonged line of “metabolic syndrome” and diabetes which my late aunt traced back to the 18th Century or further, however the presentation varies a lot: most people have some symptoms but few have the full set including Type 2 diabetes, and even more curiously the severity is negatively associated with obesity. So there’s obviously something genetic going on, but significantly modified either by other genes (IMO they aren’t additive but mulitplicative in effect) and almost certainly by environmental factors.

    I’m with Mark Sisson

    using dietary and other factors to moderate the expression of the genes seems to be working, looking at the significant improvements in my BG, lipids and BP.

    Considering that my dietician was the only person who actually caused me to gain weight I am absolutely convinced that the opposite is also true. the current dietary orthodoxy and other factors of “modern” life all conspire to express the genes in all carriers.

    In a different environment these fuel efficiency genes would probably have been beneficial, but in a land of constant carbs they are a major disbenefit. We are the canaries in the coalmine in that we respond worse and earlier to the same environmental factors that are acting negatively on the rest of the population too.

    There’s quite a bit on intermittent fasting here

    this does NOT work with my gene set as it causes my liver to panic and dump hordes of unwanted glucose, but many find it effective. However by balancing protein and sat fats with minimal carbs I can often go 6 hours without snacking while remaining active and keeping my BG even, that’s about the best I am allowed to do.

  9. Chris 4 June 2009 at 5:29 pm #

    Thanks Paul,
    I have navigated to
    I haven’t had chance to cruise around it yet.
    Front page it does look very slick and marketable and, in itself, that does induce some scepticism within me. It suggests affirmation of the notion that we must confirm to some physical perfection as perpetrated by the ‘glossies’. I guess I have seen too many summers. Still, if the advice within is sensible I could forgo my prejudice. Perhaps younger folks have a different take on things and maybe it is a good thing if this appeals to them?

  10. Chris 4 June 2009 at 8:33 pm #

    IF = ‘Intermittent Fasting’, ‘Intermittent Feeding’, ( or ‘Invalidated Fad’ !?)
    I don’t know because I didn’t shell out $29 (full price $49) for the break free book. I detected much froth but discerned little body to the sales pitch and so kept my card under wraps. Splashing around in the forums there were some darn fool questions.

    Paul, I agree with your observations that some folks appear to lose control of the ability to self regulate appetite – what other explanation can there be for human adults attaining weights of a quarter tonne and needing demolition of walls and flatbed wagons to transport them for care? And of course, loss of this ability may apply in far less extreme instances.
    I also agree that raised insulin levels, in response to a high glucose load in the blood, are probably largely factorial in weight gain and developing insulin resistance. In truth I’m not adequately qualified to direct you or others in this, but I do reflect opinions of those who are. Additional to that I can factor in personal experience.
    A while before I was diagnosed diabetic, I had a period of enforced fasting due to a particularly nasty attack of flu, the real McCoy – not just man flu. When i returned to work I noticed two things, one was being decidedly lighter on my feet and having a spring in my step, and two, having considerably better control over my appetite; I craved pies and pasties far less. It was a nice place to be.
    So that sounds like an endorsement in favour of fasting, yeah?
    No, fasting, voluntary or otherwise, does not make sense to me, and here’s why:

    Our body is comprised of trillions of cells (lets not be pedants over the numbers) who do not know or care that we exist (thanks to Bill Bryson for that eloquence) and whose needs must be met for optimal efficiency. Our cells are constantly replicating and dying and we are constantly poohing out the detritus. Cells are short lived and even skeletons exist in a constant flux of renewal so that seven years from now not one component of you will be the same; not even the molecules that make up your bones. This places a great deal of responsibility upon the owner of the body to meet the needs of his or her constituent cells. The cells need energy and a lot of essential nutrients – 24/7, 52/52. Cells can only store energy in minute amounts, see, but fortunately by the marvel of nature some of our cells are organised into organs that can buffer energy digested from food and release it when our blood sugar drops between meals. Our organs give us some freedom from having to constantly feed our cells so that we can politely exchange ideas on forums such as this. It is marvelous that the body can be so adaptable as to go without food for periods, even long periods, and recover, my car can run with oil level even below minimum for a while, but I am not sure that it is a good idea. In each case, I think there may be an element of stress and risk involved to the systems that keep things going.

    If people feel better for fasting that likely may be an indicator of raised insulin levels or metabolic dysfunction (Doc?) and if a fast helps break that cycle, reintroduces better balanced dietary habits, and reduces cravings then that is arguably helpful, but not necessarily optimal.
    Fasting, intermittent feeding, at least my pre-conception of what that may mean, as regular and cyclical habit would seem to me to add to the stress of an already stressed physiology. I’m no doc. Dr Briffa may be able to correct me if I’m wrong.

  11. Margaret Wilde 28 June 2009 at 9:52 pm #

    To lose weight you need to avoid salt and salty food and to eat low sodium food instead. Potassium-rich food and drink will also help because potassium displaces some of the excess sodium from the body. Lower sodium intake and higher potassium intake result in reduced fluid retention, fluid retention being the initiator of weight gain.

    People who are overweight tend to be sensitive to salt, whereas slim people are not sensitive to salt.

  12. suzan 3 March 2010 at 1:25 am #

    nice article about potassium…very informative and beneficial for me…thx

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