Energy and Macronutrient Intake in the Midwest Exercise Trial-2 (MET-2).

PURPOSE:

To examined the effect of exercise training over 10 months at 2 levels of energy expenditure on energy and macronutrient intake in a sample of previously sedentary, overweight/obese young adults.

METHODS:

We conducted a 10 month trial in 141 young adults who were randomized to supervised exercise, 5 days•wk at 400 and 600 kcal•session, or non-exercise control. Participants were instructed to maintain their usual ad-libitum diets. Energy/macronutrient intake was assessed at baseline, 3.5, 7 and 10 months over 7-day periods of ad libitum eating in a university cafeteria using digital photography. Foods consumed outside the cafeteria were assessed using multiple-pass recalls.

RESULTS:

There were no significant between group differences in absolute energy intake at baseline or any other time point in the total sample or in men. In women, absolute energy intake was significantly greater in the 600 kcal•session group vs. controls at both 3.5 and 7 months. There were no significant between group differences in relative energy intake (kcal•kg•d) at any time point in the total sample, men or women. There were no significant within or between group differences of change in absolute or relative energy intake in any of the 3 study groups in the total sample, or in men or women. No clinically relevant changes in macronutrient intake were observed.

CONCLUSION:

Aerobic exercise training does not significantly alter energy or macronutrient intake in overweight and obese young adults. The possibility of a threshold level beyond which increased exercise energy expenditure fails to produce a more negative energy balance, and potential sex differences in the energy intake response to increased levels of exercise are potentially important.