1a. Objectives (from AD-416):
Collaborate in planning, implementation and reporting of research on the effects of diet and physical activity in maintaining healthy body weight.
1b. Approach (from AD-416):
Human volunteers will be studied under a variety of diety conditions and physical activity regimens, and biochemical and functional parameters will be measured.
3. Progress Report:
Studies were conducted to determine the effect of dietary protein level of the status of muscle protein and bone mineral during a 30-day period of negative energy balance. This was done in young men and women volunteers who lived in our metabolic unit and were subjected to a 30% energy deficit by dietary means with a 10% increase in energy output by prescribed physical activity. Bone mineral was evaluated by the retention of an infuse dose of stable calcium; protein accretion was determined by the uptake of an infused dose of stable isotopically labeled amino acids into samples of thigh muscle collected by biopsy. The active experimental phase of this study was completed in FY2012; samples are being analyzed. Results show that moderately increased protein intake can reduce the loss of muscle protein that occurs under conditions of negative caloric balance in exercising men and women.