Changes in regional body composition over 8 years in a randomized lifestyle trial: The look AHEAD study.

OBJECTIVE: To test the hypothesis that an 8-year intensive lifestyle intervention (ILI) suppresses aging-dependent changes in regional lean mass (LM) and fat mass (FM) among people with overweight/obesity and type 2 diabetes. METHODS: Regional body composition was measured by dual-energy X-ray absorptiometry within a subset of 1,019 volunteers (45-75 years old) in the Look AHEAD study randomized to ILI or diabetes support and education (DSE). The ILI goal was to achieve and maintain ≥7% weight loss through increased physical activity and reduced caloric intake. RESULTS: Over 8 years, the DSE group exhibited a linear loss of LM and FM. During year 1, the ILI group lost LM and FM. Between years 1 and 8, the ILI group regained most FM in all regions; regional LM converged with that of the DSE group; the percent of LM loss was greater for the leg than for the trunk. Among both groups, regional LM and FM change was proportional to the size of the region, trunk > leg > arm. CONCLUSIONS: Aging-dependent LM losses, particularly in the leg region, were not suppressed by ILI. The long-term consequences of rapid LM and FM loss and subsequent regain mostly as fat are unknown.

Changes in body composition over 8 years in a randomized trial of a lifestyle intervention: the look AHEAD study.

OBJECTIVE: To determine the effects of an intensive lifestyle intervention versus a comparison group on body composition in obese or overweight persons with type 2 diabetes at baseline and at 1, 4, and 8 years. METHODS: Body composition was measured by dual-energy X-ray absorptiometry in a subset of 1019 Look AHEAD study volunteers randomized to intervention or comparison groups. The intervention was designed to achieve and maintain ≥7% weight loss through increased physical activity and reduced caloric intake. The comparison group received social support and diabetes education. RESULTS: At 1 year, the intervention group lost fat (5.6 ± 0.2 kg) and lean mass (2.3 ± 0.1 kg) but regained fat (∼100%) and lost lean mass between years 1 and 8. Between baseline and year 8, weight loss was greater in intervention versus comparison groups (4.0 ± 0.4 vs. 2.3 ± 0.4 kg); comparison group weight loss was mostly lean mass (2.1 ± 0.17 kg). Fat mass in the intervention group was lower than that of the comparison group at all post-baseline time points. CONCLUSIONS: Reduced fat mass may place the intervention group at a lower risk of obesity-linked sequelae, a hypothesis that can be tested by future studies of this cohort.