Effect of alcohol on postmeal fat storage

Energy expenditure and macronutrient balances were assessed in normal healthy men by whole-body indirect calorimetry after meals consumed with and without ethanol to test the theory that alcohol energy is not fully available because of futile cycling. Alcohol addition (A) or isoenergetic substitution (S) caused fat retention by significantly suppressing its oxidation when the alcohol was actively metabolized (0-6h). However, on protocol S, fat balance was later reestablished due to raised fat oxidation (6-20.5 h) secondary to a relative carbohydrate deficiency. On protocol A, fat balance remained significantly raised. The thermogenic effect of alcohol was similar to that of carbohydrate, providing no evidence for futile cycling. Short-term studies that fail to account for later readjustments of macronutrient balance can be misleading. We conclude that alcohol has a fat-sparing effect similar to that of carbohydrate and will only cause fat gain when consumed in excess of normal energy needs.