Resumen de Effects of Exercise on Postprandial Responses to Ad Libitum Feeding in Overweight Men

Nor M.F. Farah, Dalia Malkova, Jason M.R. Gill

• Purpose: Previous exercise reduces the lipemic response to meals of fixed size. It is not known whether this triglyceride (TG) attenuation also occurs in response to feeding because exercise might induce a compensatory increase in energy intake. It is also unclear whether the effects of a single exercise session on lipemia would be augmented by repeated exercise sessions on consecutive days.

  Design: Ten sedentary overweight/obese men (aged 35 ± 6 yr) each participated in three 4-d trials in random order: CON (no exercise on days 1-3), EX-1 (exercise session on day 3), and EX-3 (exercise sessions on days 1-3). Each exercise session expended 33.5 kJ·kg body mass. Subjects consumed an isocaloric diet (provided by experimenters) and avoided alcohol on days 1-3 of all trials. On day 4 of each trial, participants underwent a 7-h metabolic assessment, during which an buffet breakfast and lunch was provided, and postprandial plasma and expired air responses were assessed.

  Results: Day 4 energy intake was higher than CON in EX-3 (9216 ± 669 vs 7859 ± 492 kJ, < 0.05) but not EX-1 (8335 ± 683 kJ). Postprandial TG responses were 27% and 25% lower in EX-1 and EX-3, respectively, than in CON (both < 0.05), and postprandial insulin responses were 26% ( = 0.06) and 31% ( < 0.05) lower in EX-1 and EX-3, respectively, than in CON. Compared with CON, postprandial fat oxidation was 20% higher in EX-1 and 27% higher in EX-3 (both < 0.05).

  Conclusions: Previous exercise attenuates the lipemic response to meals, suggesting that exercise's TG-lowering effect will extend into "real-world" settings where food intake is not carefully controlled. This response is not augmented by exercising on repeated days.