CONTEXT:

Physical inactivity contributes to weight gain, but only 22% of Americans are regularly active.

OBJECTIVE:

To examine short- and long-term changes in weight, body composition, and cardiovascular risk profiles produced by diet combined with either structured aerobic exercise or moderate-intensity lifestyle activity.

DESIGN:

Sixteen-week randomized controlled trial with 1-year follow-up, conducted from August 1995 to December 1996.

PARTICIPANTS AND SETTING:

Forty obese women (mean body mass index [weight in kilograms divided by the square of height in meters], 32.9 kg/m2; mean weight, 89.2 kg) with a mean age of 42.9 years (range, 21-60 years) seen in a university-based weight management program.

INTERVENTIONS:

Structured aerobic exercise or moderate lifestyle activity; low-fat diet of about 1200 kcal/d.

MAIN OUTCOME MEASURES:

Changes in body weight, body composition, cardiovascular risk profiles, and physical fitness at 16 weeks and at 1 year.

RESULTS:

Mean (SD) weight losses during the 16-week treatment program were 8.3 (3.8) kg for the aerobic group and 7.9 (4.2) kg for the lifestyle group (within groups, P<.001; between groups, P = .08). The aerobic group lost significantly less fat-free mass (0.5 [1.3] kg) than the lifestyle group (1.4 [1.3] kg; P = .03). During the 1-year follow-up, the aerobic group regained 1.6 [5.5] kg, while the lifestyle group regained 0.08 (4.6) kg. At week 16, serum triglyceride levels and total cholesterol levels were reduced significantly (P<.001) from baseline (16.3% and 10.1% reductions, respectively) but did not differ significantly between groups and were not different from baseline or between groups at week 68.

CONCLUSIONS:

A program of diet plus lifestyle activity may offer similar health benefits and be a suitable alternative to diet plus structured aerobic activity for obese women.