Energy replacement attenuates the effects of prior moderate exercise on postprandial metabolism in overweight/obese men.

Abstract

The extent to which exercise-induced changes to postprandial metabolism are dependant on the associated energy deficit is not known. To determine the effects of exercise, with and without energy replacement, on postprandial metabolism. Each subject underwent three 2-day trials in random order. On day 1 of each trial subjects rested (control), walked at 50% maximal oxygen uptake to induce a net energy expenditure of 27 kJ kg(-1) body mass (energy-deficit) or completed the same walk with the net energy expended replaced (energy-replacement). On day 2 subjects completed an 8.5-h metabolic assessment. For 3 days prior to day 2, subjects consumed an isocaloric diet, avoided planned exercise (apart from exercise interventions) and alcohol. A total of 13 overweight/obese men (age: 40+/-8 years, body mass index: 31.1+/-3.0 kg m(-2)). Postprandial triglyceride, insulin, glucose, non-esterified fatty acid and 3-hydroxybutyrate concentrations and substrate utilization rates were determined. Energy-deficit lowered postprandial triglyceride concentrations by 14 and 10% compared with control and energy-replacement (P<0.05 for both). Energy-deficit increased postprandial 3-hydroxybutyrate concentrations by 40 and 19% compared with control and energy-replacement (P<0.05 for both). Postprandial insulin concentrations were 18 and 10% lower for energy-deficit and energy-replacement compared with control and 10% lower for energy-deficit than energy-replacement (P<0.05 for all). Postprandial fat oxidation increased by 30 and 14% for energy-deficit and energy-replacement compared to control and was 12% higher for energy-deficit than energy-replacement (P<0.05 for all). Exercise with energy replacement lowered postprandial insulinaemia and increased fat oxidation. However an exercise-induced energy deficit augmented these effects and was necessary to lower postprandial lipaemia.