Grant: Travel Awards - Institute Community Support

The progressive loss of muscle mass with age is associated with increased risk for numerous negative outcomes such as falls, disability and death. Further complicating this scenario, rates of obesity are rising among older adults. Although fat mass loss can have many health benefits for obese older adults reduced calorie diets may also accelerate muscle loss. Therefore there is a critical need to identify lifestyle strategies that facilitate simultaneous fat mass loss and muscle mass preservation. We compared the influence of a balanced (even) and a skewed (traditional) distribution of dietary protein over the daily meals on the rate of muscle building in older men during weight maintenance (WM), calorie restriction alone (CR alone) and calorie restriction plus resistance (weightlifting) training (CR+RT). Twenty overweight/obese older men were allocated to either the balanced or the skewed group and were provided with a 4-wk reduced calorie diet. In the balanced group protein was spread evenly over the four daily meals and in the skewed group the majority (72%) of protein was consumed in the evening meal. In weeks 1 and 2 of the diet (CR alone) participants continued their habitual physical activity and in weeks 3 and 4 of the diet (CR+RT) participants performed supervised resistance training. Rates muscle building were measured with a balanced and a skewed pattern of protein intake during WM, CR alone and CR+RT. We found that CR alone resulted in a reduction in the rate of muscle building compared to WM in both groups but rates were higher with a balanced distribution of daily protein compared to a skewed distribution. Combining RT with a balanced protein distribution during CR restored rates of muscle building to the higher WM levels. In conclusion, the combination of balanced distribution of daily protein and RT may represent an effective strategy to support fat mass loss without accelerating muscle loss in overweight/obese older adults.