Effect of energy and protein intake and exercise intensity on the thermic effect of food.

The effect of energy content and protein concentration of a test meal and exercise intensity on the thermic effect of food (TEF) was examined. TEF was measured in eight men in response to meals representing 15, 30, and 45% of daily energy requirement; protein concentrations of 15, 30, and 45% of energy of the meal, and exercise intensities of 35, 50, and 65% of maximum capacity. In response to energy content of the meals, total 3-h TEF (mean +/- SEM) 4.0 +/- 0.83, 9.7 +/- 1.15, and 10.8 +/- 0.79 1 O2 for the 15, 30, and 45% meals, respectively, indicating a positive linear and a negative quadratic relationship. Although the 15% protein meal resulted in the smallest TEF, 150-270 min after the meal, total 5-h increase in oxygen consumption did not differ among the three protein meals. Exercise intensity did not alter TEF. Energy content of the test meal had the greatest effect on TEF.