We are told by the ‘experts’ who control our lives that when we get fat it is because we eat too much and do too little. This ‘eat-too-much, do-too-little’ theory of weight gain is ‘common knowledge’ to most and so few stop to questions its validity. However, the scientific literature does not support the contention that excessive adipose tissue accumulation is caused by either greed or laziness. Firstly, forced calorie restriction and exercise does not cause long term improvements in body composition in the obese, suggesting that true energy deficits are not created in such situation. Secondly, overfeeding studies show that excess calories do not cause fat accumulation in some individuals, and some are able to gain skeletal muscle on high calorie intakes. Therefore energy surpluses do not necessarily cause body fat accumulation. This suggests that energy can be readily turned to heat in some individuals and that counterregulatory energy efficiency is able to prevent weight loss when conditions are not suited to such.
Another nail in the coffin of the ‘eat-too-much, do-too-little’ theory of weight gain is the interesting metabolic weight modulation effects of alcohol. Alcohol contains 7 kcal per gram, and we are told will make you fat if you drink too much. However, again, evidence does not support this viewpoint, as drinking alcohol is associated with a lower body weight compared to being teetotal. For example, in one study1, researchers used data from the National Health and Nutrition Examination Survey (HANES I) to investigate the associations between alcohol consumption, energy intake and relative body weight. The results showed that drinkers had significantly higher intakes of total calories than nondrinkers, mainly due to the extra calories provided by the alcoholic drinks. This would suggest that they should have had higher body weights, based on the ‘eat-too-much, do-too-little’ theory of weight gain. However, this was not the case as those who drank alcohol had lower body weights despite higher total energy intakes.
When analysis of the data was performed, the researchers discovered that as alcohol consumption increased, consumption of other calories decreased concomitantly. In particular, high intakes of alcohol were associated with lower intakes of carbohydrates. A number of explanation for the higher energy intakes and lower body weights of drinkers have been suggested. The lower carbohydrate intakes of drinkers may include a decrease in energy from sugar. Because fructose is implicated in obesity, and a molecule of fructose is present in sugar, it might be that alcohol drinkers have lower intakes of obesogenic carbohydrate compounds. Further, alcohol is known to upregulate the MEOS enzyme system in the endoplasmic reticulum of liver cells. Alcohol may therefore be metabolised through non-energy producing pathways, producing heat. The lower intake of carbohydrates and the fact that alcohol increases the thermic effect of food, could jointly explain the weight loss effect of alcohol.
RdB
