This study examined the metabolic response to a 763-kcal mixed meal at rest and during 30 min of exercise at 50% maximal oxygen consumption () in 8 aerobically trained (AT), 8 resistance trained (RT), and 8 untrained (UT) subjects. Oxygen consumption (VO,) was measured minute by minute during 30 min of exercise by indirect calorimetry on 2 nonconsecutive days (postabsorptive exercise, PA; and postprandial exercise, PP). Total VO, consumed and total caloric expenditure during the PA and PP conditions were similar for the three groups, indicating that prior food intake did not affect energy expenditure during exercise. Consequently, TEM during exercise did not differ significantly among the groups. Respiratory exchange ratio (R) differed significantly only during the PA condition, with the AT group exhibiting significantly lower R values compared to the RT group, and significantly lower R values compared to the UT group. These data suggest that the consumption of a meal 30 min prior to exercise does not increase TEM during exercise in AT, RT, and UT subjects.
J.A. Gilbert is with the Physical Education Dept. at California State University-San Bemardino, 5500 University Pkwy., San Bernardino, CA 92407. J.E. Misner is with the Physical Fitness Research Lab at the University of Illinois, 906 S. Goodwin, Urbana, IL61801.