Study: NCT03074643

Intervention type: BEHAVIORAL
Group type: ACTIVE_COMPARATOR
Intervention: Weight loss intervention months 0-6
Description: 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).

Intervention type: BEHAVIORAL
Group type: ACTIVE_COMPARATOR
Intervention: Weight loss intervention months 0-6
Description: 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).

Intervention type: BEHAVIORAL
Group type: PLACEBO_COMPARATOR
Intervention: Weight loss intervention months 0-6
Description: 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).

Intervention type: BEHAVIORAL
Group type: ACTIVE_COMPARATOR
Intervention: Exercise intervention months 0-6
Description: 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.

Intervention type: BEHAVIORAL
Group type: ACTIVE_COMPARATOR
Intervention: Exercise intervention months 0-6
Description: 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.

Intervention type: BEHAVIORAL
Group type: PLACEBO_COMPARATOR
Intervention: Exercise intervention months 0-6
Description: 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.

Intervention type: DIETARY_SUPPLEMENT
Group type: PLACEBO_COMPARATOR
Intervention: Carbohydrate supplement for months 0-6
Description: Participants in the lower protein / higher CHO diet group (RecProt) will be provided a carbohydrate supplement (\~50 g of carbohydrate and 220 calories) to consume daily during the 6 month weight loss intervention.

Intervention type: DIETARY_SUPPLEMENT
Group type: ACTIVE_COMPARATOR
Intervention: Protein supplement for months 0-6
Description: Participants in the higher protein / lower CHO diet groups (6-mon HiProt and 18-mon HiProt) will be provided a protein supplement (\~50 g of protein and 220 calories) to consume daily during the 6 month weight loss intervention.

Intervention type: DIETARY_SUPPLEMENT
Group type: ACTIVE_COMPARATOR
Intervention: Protein supplement for months 0-6
Description: Participants in the higher protein / lower CHO diet groups (6-mon HiProt and 18-mon HiProt) will be provided a protein supplement (\~50 g of protein and 220 calories) to consume daily during the 6 month weight loss intervention.

Intervention type: DIETARY_SUPPLEMENT
Group type: ACTIVE_COMPARATOR
Intervention: Protein supplement for follow-up months 7-18
Description: Participants in the higher protein / lower CHO diet (18-mon HiProt) will be provided a protein supplement (\~50 g of protein and 220 calories) to consume daily during the 12-month follow-up.