Many people who should know better are still lost in old nutritional paradigms. One such paradigm states that overeating is the cause of obesity. Proponents of such a belief, who include that vast majority of the mainstream medical establishment, assume that too little exercise and too much food result in a positive energy balance, and it is this that causes weight gain. Superficially this theory sounds plausible based on the laws of thermodynamics, but a deeper look at the science that has investigated the matter shows that evidence to date does not support the contention that overeating is the cause of obesity. Many people pass through life paying little attention to how much they eat, and yet remain well within their natural body weight ranges. So what is the differences between the behaviour of the lean and the behaviour of the obese? Increasingly it is being shown that those who get fat, do so because they eat low quality, processed and refined foods, that are devoid of meaningful levels of essential nutrients.
This eating pattern typifies the Western diet that has become common in developed nations. And it is not coincidence that obesity is reaching epidemic proportions in the Western nations of Europe, North America and Australasia. In fact studies that have investigated the traditional diets have shown that adoption of such diets, characterised by whole grains, fruits and vegetables, high quality protein, fish, fibre and high concentrations of vitamins and minerals, results in weight loss without any requirement for conscious energy restriction or exercise. Biochemical studies investigating the changes that occur during such a transition highlight the reversal of insulin resistance as a pivotal factor in the success of such diets. As insulin resistance is reversed, fasting insulin levels fall, and this removes the inhibitory effect that insulin can have on catabolic metabolic pathways. As a result normal energy metabolism is returned, and the oxidation of fuels, appetite and energy storage are all returned to their pre-dysfunctional state.
Many studies have shown inverse associations between biomarkers for high quality diets and obesity. Generally, as the typical Western diet is devoid of meaningful levels of plant foods, the biomarkers for such plant foods are often low in the obese. For example, a study1 conducted in children of Mexican descent in the United States investigated the blood concentrations of vitamin E and carotenoids and found an association between the serum concentrations of the two phytonutrients with the adiposity of the children. In particular, serum concentrations of α-carotene, trans-β-carotene, cis-β-carotene and α-tocopherol were inversely associated with the body mass indices of the children as well as truncal fat mass and total body fat mass. As vitamin E and the carotenoids are generally present only in foods of plant origin, this may suggest that the lean children were more likely to eat more plant foods, suggesting the obese children may have been eating a diet containing lower quality Western style diet.
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