Effects of Short-term Energy Deficit on Muscle Protein Turnover

Weight loss through energy restriction results in the loss of both fat and muscle mass. Muscle mass is important for mobility, strength, glucose control and energy expenditure, and therefore the retention of muscle mass during energy restriction is an important goal. The retention of muscle mass depends on the balance between muscle protein synthesis (MPS) and muscle protein breakdown (MPB). It is well known that MPS is reduced during weight loss, however the effect of weight loss on MPB is currently a topic of debate. The purpose of this study is to assess the effect of short-term (10 day) weight loss (40% energy deficit) on both MPS and MPB in order to gain insight into the mechanisms causing muscle loss during energy restriction. In addition, the effect of resistance exercise and protein (both known to preserve muscle mass) on MPS and MPB will be examined