| Abstract: | Prior exercise potentiates the thermic effect of a carbohydrate meal. The purpose of this study was to determine if meal size or feeding pattern influences this response. Two groups of healthy, normal-weight young women exercised for 45 min on a cycle ergometer at 70% of maximal aerobic capacity. Once aerobic capacity returned to pre-exercise baseline, the thermic effect of food (TEF) was determined by indirect calorimetry over a 2-h period. One group of subjects ingested a 2510-kJ meal and the other a 5020-kJ meal. As a control, subjects ingested the test meal without prior exercise. In addition, subjects ingesting the 5020–kJ meal were studied for an additional 2 h. In a separate trial, these subjects ingested a 5020-kJ meal in two equal portions after a bout of exercise, the second portion 120 min after the first. TEF was less for the 2510-kJ meal compared with the 5020-kJ meal for both the control [mean (SE), 76 (17) vs 158 (19) kJ · 2h–1,P < 0.01), and prior exercise [124 (23) vs 197 (24) kJ · 2h–1,P<0.01) trials. However, the same increment in TEF resulted from the prior bout of exercise [48 (9) vs 40 (8) kJ · 2h– for 2510-and 5020-kJ meals, respectively). TEF was 31 % lower when the 5020-kJ meal was given in two portions compared with one [281 (30) vs 369 (41) kJ · 4h–1, P < 0.05]. No difference in TEF was found between the first and second 2510-kJ portion. The results suggest that potentiation of TEF by prior exercise is not influenced by caloric density or energy content of the meal. Rather, meal volume and hence meal frequency is a greater determinant of postexercise TEF. |
