Feeding frequency and energy balance in adult males.

Eight young adult males were fed isoenergetic diets of similar composition either in two meals or in six meals per day at defined times. While on each dietary regimen for two weeks the subjects occupied a whole body calorimeter for two 31-h periods, during which they followed a prescribed activity pattern. For each individual the 24-h energy expenditure in the calorimeter was highly reproducible and no discernible effect of meal frequency was observed under these controlled conditions. The total expenditure in the calorimeter on both regimens was substantially less than the energy intake and a progressive small weight gain was observed throughout the 2-week period on the two-meal-a-day system. If feeding frequency alters metabolic efficiency then it does so by mechanisms not readily discernible in a whole body calorimeter.