Energy balance changes the anabolic effect of postexercise feeding in older individuals.

We previously showed that consumption of protein immediately after exercise in older adults enhances nitrogen balance when energy balance (EB) is maintained. Because daily EB routinely varies, it is important to know whether benefits of postexercise protein consumption also occur with changing EB. Within an experiment, participants consumed an isonitrogenous-isocaloric diet with the timing of a protein (PRO + CHO) or carbohydrate (CHO) beverage immediately after exercise versus earlier in the day. Within hypocaloric and hypercaloric cohorts, 3-day mean nitrogen balance was not different when protein was consumed immediately after exercise, although there was a trend (p = .09) for higher nitrogen balance in the positive EB. However, when data from our three studies were combined, the anabolic effect of postexercise feeding was evident during positive EB but not negative EB. EB is therefore an important consideration in the postexercise anabolic effect of protein feeding.