Utilizing Protein During Weight Loss to Impact Physical Function and Bone

All participants will undergo a dietary weight loss intervention designed to elicit behavioral changes leading to decreased caloric intake sufficient to yield a \~10% loss of initial body mass. The weight loss intervention will incorporate nutrition education (via group and individual meetings with the study dietitian), self-monitoring skills, cognitive-behavioral strategies for promoting lifestyle behavior modifications, and planned meals. Behavioral and educational group and individual sessions will be held weekly in a 3:1 ratio (3 group and 1 individual session per month).

All participants will be expected to participate in a supervised, center-based exercise program involving moderate-intensity aerobic exercise (e.g., treadmill walking) 3 days/wk during the 6-month weight loss intervention in accordance with the American Heart Association and the American College of Sports Medicine physical activity recommendations for older adults.

Participants in the lower protein / higher CHO diet group (RecProt) will be provided a carbohydrate supplement (NutraBio™ CarboMax, \~50 g of carbohydrate and 220 calories) to consume daily during the 6 month weight loss intervention.

Participants in the 6-month higher protein / lower CHO diet group (6-mo HiProt) will be provided a protein supplement (NutraBio™ 100% Whey Protein Isolate, \~50 g of protein and 220 calories) to consume daily during the 6 month weight loss intervention.

Participants in the 18-month higher protein / lower CHO diet (18-mo HiProt) will be provided a protein supplement (NutraBio™ 100% Whey Protein Isolate, \~50 g of protein and 220 calories) to consume daily during the 6 month weight loss intervention and the 12-month follow-up.