Energy replacement diminishes the effect of exercise on postprandial lipemia in boys

PurposeAcute bouts of exercise reduce postprandial triacylglycerol concentrations ([TAG]) in healthy boys and girls; however, it is not known whether this effect is mediated by the energy deficit. This study examined whether the exercise-induced reduction in postprandial [TAG] persists after immediate dietary replacement of the exercise energy expenditure (EE).MethodsEighteen healthy 11- to 13-year-old boys (mean (SD): body mass 41.3 (8.4) kg; peak oxygen uptake (V̇O2) 55 (5) mL·kg− 1·min− 1) completed three, 2-day conditions in a within-measures, crossover design separated by 14 days. On day 1, participants rested (CON), exercised at 60% peak V̇O2 inducing a net EE of 32 kJ·kg− 1 body mass (EX-DEF) or completed the same exercise with the net EE replaced immediately (EX-REP). On day 2, capillary blood samples were taken in the fasted state and at pre-determined intervals throughout the 6.5 h postprandial period. A standardised breakfast and lunch meal were consumed immediately and 4 h, respectively, after the fasting sample.ResultsBased on ratios of the geometric means (95% confidence intervals (CI) for ratios), EX-DEF fasting [TAG] was 19% and 15% lower than CON (− 32 to − 4%, ES = 1.15, P = 0.02) and EX-REP (− 29 to 0%, ES = 0.91, P = 0.05) respectively; CON and EX-REP were similar (− 4%; P = 0.59). The EX-DEF total area under the [TAG] versus time curve was 15% and 16% lower than CON (− 27 to 0%, ES = 0.55, P = 0.05) and EX-REP (− 29 to − 2%, ES = 0.62, P = 0.03) respectively; CON and EX-REP were not different (2%; − 13 to 20%, P = 0.80).ConclusionImmediate replacement of the exercise-induced energy deficit negates the reduction in postprandial [TAG] in boys; this highlights the importance of maintaining a negative energy balance immediately post-exercise to maximise the metabolic health benefits of exercise.