The ‘eat-too-much, do-too-little’ theory of obesity claims that excessive weight gain is the result of greed and laziness on the part of the individual. The solution to this behaviour, we are told, is a forced regimen of a low energy diet in combination with vigorous exercise, in order to create a negative energy balance. While it is true that there is an association between overeating and obesity, the cause and effect has been misunderstood. Obesity is a metabolic disorder characterised by insulin resistance and an inability to compartmentalise energy to the correct location. The characteristic high insulin levels interfere with the leptin signal to the hypothalamus and induce leptin resistance. This ‘tricks’ the hypothalamus into thinking energy stores are low, and in response stimulates appetite, reduces physical activity and decreases resting metabolic rate (RMR). No amount of forced physical activity or dieting can override this metabolic dysfunction.
That forced calorie restriction is not effective against obesity is well reported in the literature. However, most of the evidence is disregarded by proponents of the ‘eat-too-much, do-too-little’ hypothesis of weight gain. For example, researchers1 investigated the effects of a whole wheat diet containing a special expanded whole wheat protein on weight loss in obesity females. The wheat product had been expanded with air to increase its volume. The diet contained only 1000 kcal per day and was therefore considered a low calorie diet. Over the course of 6 weeks the subjects lost 3.9 kg in body weight and then a further 1.6 kg over the next 6 weeks. However, that this was not down to calorie restriction was proven by a control group that had the same 1000 kcal diet but without the whole wheat products. The control group lost 2.8 kg during the first 6 weeks and then failed to make further losses.
Interestingly the researchers reported that the whole wheat diet had caused beneficial changes to blood lipids. In particular, reductions in total cholesterol and triglycerides were reported. This is consistent with other studies that have reported improvements in blood lipids from consumption of whole grain products. Increasing intake of whole grain products is known to increase the quality of the diet, and this in turn may decrease the flux of nutrients through the liver, thus reducing nutrient overload. This overload is thought to be a cause of the development of abdominal obesity and insulin resistance. Whole grains therefore reverse abdominal obesity, which explains both the weight loss and the improvements in blood lipids. The low calorie diet in contrast caused short-term weight loss, that was not sustainable, because it did not address the underlying cause of the weight gain. Weight loss likely stopped because of a downward adjustment to RMR.
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