High GI diet leads to reduced fat-burning and increased fatness in mice

As a general rule, scientists, doctors and dieticians subscribe to the view that when it comes to weight management, ‘a calorie is a calorie’. Essentially, this means that weight loss is the aim, we need to consume fewer calories than we burn, and as long as we do, then the form that these calories come in is irrelevant. Actually, as I pointed out in a blog post a few weeks ago, there is some evidence that the type of calories (irrespective of the number of calories we consume) we ingest may influence weight control. This blog post highlights a mouse study which found that low-carb diet brought about a similar level of weight loss similar to that seen in mice eating a standard diet of significantly lower energy content.

More recently, I noticed another mouse study which suggests that not all types of calories are created equal when it comes to effects that relate to body weight. In this study, mice were fed with diets of either high or low-GI (fast or slow sugar-releasing nature respectively) [1]. In each case, the mice were fed the same number of calories.

Feeding the mice the high-GI was found to down-regulate fat burning (fat oxidation) in the body compared to the low-GI diet. This difference was noted as early as three weeks after the experiment started. And as time went on, this effect appeared to contribute to other differences as well, namely higher body fat levels, as well as levels of fat in the liver.

Now, remember, the number of calories fed to these mice was the same. So, any differences between groups were the result of the dietary composition. Basically, the higher GI diet was found to reduce the metabolism of fat and lead to increased levels of fatness. It should perhaps be borne in mind that higher GI foods tend to cause more insulin secretion than lower-GI ones. This is relevant, as insulin has effects which impair fat metabolism while encouraging fat manufacturing by the body.


1. Klaus IF, et al. Impairment of fat oxidation under high vs low glycemic index diet occurs prior to the development of an obese pehnotype. Am J Physiol Endocrinol Metab 24 Nov 2009 [epub ahead of print]

7 Responses to High GI diet leads to reduced fat-burning and increased fatness in mice

  1. Peter Silverman 1 December 2009 at 2:35 pm #

    Cat and Mouse

    A friend of mine put his fat, diabetic cat on a low carb diet. The cat went into shock, because her blood sugars returned to normal and my friend, who had been giving the cat insulin shots for five years didn’t realize it. The cat survived, and has lost a third of it’s body weight, and no longer needs insulin shots.

  2. Ali 2 December 2009 at 4:08 am #

    shouldn’t cats eat a low carb diet in the first place? I feed mine meat

  3. Paul Anderson 4 December 2009 at 4:27 pm #

    Shouldn’t humans also eat a low carb diet?

  4. Iain Dobson 4 December 2009 at 9:54 pm #

    I would suggest people interested in this subject read Gary Taubes book, “The Diet Delusion” available for under £10 on line. A very well written and researched book.

  5. Sherry 4 December 2009 at 10:02 pm #

    As silly as it sounds, most “diabetic” (and weight-reducing i.e.Light) cat food is low fat,high carb. Lots of lovely cereal and heart-healthy sunflower oil !

    It`s what keeps the Vets in business.

  6. george kaposhilin 5 December 2009 at 2:14 am #

    what are examples of low GI carb foods

  7. Chris 14 May 2010 at 3:43 pm #

    george, by definition carb foods are high GI but nature does provide some foods that are relatively high in carbohydrate but which qare also high in fibre. High fibre can reduce the GI of carb rich foods.

    Peter, Diabetes is growing amongst domestic pets because of the economic expediency and increase use of cereal based pet foods. Diabetes UK had web pages devoted to diabetes in pets but when opinion was expressed elsewhere on the web that this constituted an own goal by Diabetes UK to inadvertently cast light upon one possible contributory factor leading to increased incidence in humans the pet pages ‘disappeared.’ Diabetes UK interests (alledgedly) lie with treatment not absolution of causality.

    High GI seems to induce some kind of addiction. The symptom seems to be loss by some degree of the capacity to to self regulate appetite and to self regulate weight management.
    Is GI the key to unlocking a hidden addiction? High GI relates to the mechanism for conversion of high postprandial blood sugar and raised insulin to body fat but does something such as a hidden addiction a honey-trap that is difficult to avoid?

Leave a Reply