The cumulative effects of seven days of imposed exercise on energy balance and appetite regulation

Abstract

Increasing energy expenditure (EE) through regular exercise is a promising strategy to prevent body fat gain. However, imposed exercise interventions often produce weight loss that is less than theoretically expected, possibility due to compensatory mechanisms in energy intake (EI) and EE. Study one was designed to determine whether a combined written and photographic food diary was a reliable measure of EI within a free-living environment across seven days. The results suggested this method was reliable at the group level. However, 95% limits of agreement (LoA) showed large variability (-1258 to 1545 kcal/day) at the individual level. Study two investigated acylated ghrelin, PYY and energy balance in response to 7-days of imposed exercise and a control condition. EI increased by 511 kcal/day in the exercise condition (P=0.005). Late-postprandial acylated ghrelin concentrations were higher in the exercise condition (P=0.072), but did not change from pre- to post intervention. There was a larger, but non-significant, increase in EI at the postprandial ad libitum pasta meal in the exercise condition (P=0.285). In conclusion, 7-days exercise resulted in increased EI under free-living conditions; similar results were found when assessed in a controlled laboratory environment. A larger sample size would allow confirmation of the findings.