Fuel Utilization and Protein Balance. (A) The effect of dietary RS on steady-state RER during the exercise bout on days 0, 1 and 65 of relapse is shown. Data on each day were examined by ANCOVA with energy balance as the covariate. Exercise RER was higher in RS-fed rats on day 1 and day 65 of relapse (* p < 0.05), suggesting a greater reliance on carbohydrate, rather than protein or fat, to provide the energy requirements during exercise. (B) The effect of dietary RS on protein disappearance and protein balance in EX/SED rats (n = 3/group) shortly before they stopped their program of exercise (day 35 of relapse) and again at the end of the relapse period (day 65 of relapse) is shown. For each parameter, a one-way repeated measure model was used to assess the impact of dietary RS and time. Dietary RS was accompanied by lower protein oxidation and a higher protein balance.