The purpose of this study is to determine how the modality of energy depletion can differently impact appetite hormones, ad libitum food intake, food hedonics, and olfaction.

The objectives of the current randomized controlled study were to examine how the modality of an acute 3 day isocaloric -25% energy depletion by dieting alone or by aerobic exercise alone differently impacts appetite and appetite-related hormones, ad libitum energy intake (EI), food hedonics and food reward, and olfaction. It was hypothesized that independent of modality of depletion, that relative to the control, there would be increased ad libitum feeding and food reward, improvements in smell performance, and a decline in fasting leptin and increase in fasting total ghrelin. It was also hypothesized that the increased food reward would prove to be a predictor of ad libitum EI and that relative to the depletion by aerobic exercise alone, the depletion by diet alone would produce greater compensatory increases in appetite, ad libitum EI, and food reward.

Statistics

To test for differences in body weight, plasma hormone concentrations, relative-reinforcing value of food (RRVF), and olfaction across each condition of the study, repeated measures ANOVA controlling for day 1 as a covariate was employed. Pairwise comparisons at day 4 using Sidak adjustment to account for multiple comparisons are reported when the ANOVA was significant. One way repeated measures ANOVAs with Sidak adjustments for multiple comparisons were used to test for differences in variables measured only at day 4: body composition (fat mas, %Fat, and fat free mass), appetite, palatability, and ad libitum EI.

Inclusion Criteria:

• Free from any illness that could influence outcome of the experiment
• Weight-stable for >6months
• aged between 18-40 years

Exclusion Criteria:

• diabetic
• smoker
• medication