Race, Menopause and Metabolism After Exercise and Diet

Overview

The purpose of this study is to test the hypotheses that there are ethnic and genetic differences in the mechanisms and magnitude by which hypocaloric weight loss and aerobic exercise affect body composition, glucose, lipid, muscle and adipose tissue metabolism in overweight, insulin resistant postmenopausal women. This will be tested in a trial comparing the effects of weight loss vs. aerobic exercise plus weight loss on glucose, lipid, fat and muscle metabolism in overweight African American and Caucasian postmenopausal women.

The findings of this study will also determine whether there are racial differences in the whole body and cellular mechanisms by which aerobic exercise training and weight loss affect glucose, lipid, fat and muscle metabolism in African-American vs. Caucasian postmenopausal women. The results also may provide a rationale for targeting specific populations of women who might improve glucose, lipid, fat and muscle metabolism more from the addition of exercise to dietary restriction than weight loss alone to reduce their risk for type 2 diabetes and cardiovascular disease. The study protocol consists of the following phases: Phase 1-Recruitment and screening. Phase 2-Weight and dietary stabilization for 4-6 weeks, where participants are taught the principles of the American Heart Association "Heart Healthy" diet and provided food to consume prior to testing. Phase 3-Participants will undergo research testing including glucose clamp and fat biopsy. Phase 4-Participants select either weight loss only, or exercise plus weight loss. The behavior diet modification weight loss sessions are held by a registered dietitian for 1 hour once a week for 6-9 months where the recommended caloric intake for each participant is adjusted by the dietitian to elicit a weight loss of approximately 0.2-0.4 kg per week. In addition to the weight loss sessions, participants who select the aerobic exercise plus weight loss intervention will exercise at the Baltimore Geriatric Research Education and Clinical Center (GRECC) exercise facility 3 times a week for 6-9 months using treadmills and other aerobic exercise equipment. Exercise sessions begin at low levels of VO2max (maximal oxygen consumption) and progress in duration and intensity until the participant is able to exercise at more than 75% VO2max for 45 minutes. Phase 5-Following the 6-9 months of long-term weight loss or exercise plus weight loss, all participants will undergo long-term metabolic testing.

Conditions

Interventions

Eligibility

Locations (1)

Outcomes