The effects of moderate protein or energy supplements on subsequent nutrient intake in man.

A moderate energy (0 g protein, 420 kcal) supplement was given daily to a group of people (n = 14) in one week, and a placebo was administered daily in another week. A second group (n = 13) was given a protein supplement (14 g protein, 84 kcal) daily during one week and a placebo in a separate week. A crossover design was used. The effect of the energy supplement was to increase the mean energy intake by 273 kcal, in the treatment compared with the placebo week. That is, 32% of the energy value of the drink was accommodated by a change in the diet; this change was not significant. The effect of the protein supplement was to increase the mean protein intake on day 1 by 20.5 g, in the treatment compared with the placebo week. This increment decreased linearly throughout the week, to 5.9 g on day 7. At lunchtime, carbohydrate intakes were significantly depressed after the protein supplement, and protein intake was significantly increased after the energy supplement.