Background: High levels of exercise may be necessary for long-term maintenance of weight loss.

Objective: We aimed to determine in a randomized prospective design whether encouraging 2500 kcal physical activity/wk produced greater 30-mo weight losses than did the standard 1000 kcal physical activity/wk prescription.

Design: Overweight adults (n = 202) were randomly assigned to either 18 mo of standard behavioral treatment (SBT) with an exercise goal of 1000 kcal/wk or a high physical activity (HPA) treatment with a goal of 2500 kcal/wk. The HPA treatment included all procedures in the SBT plus encouragement to recruit 1-3 exercise partners and small-group counseling with an exercise coach. Participants were followed for 30 mo.

Results: The HPA group achieved significantly greater exercise levels and weight losses than did the SBT group at 12 and 18 mo (P < 0.01). Weight losses did not differ significantly at 30 mo: 0.90 +/- 8.9 and 2.86 +/- 8.6 kg for the SBT and HPA groups, respectively (P = 0.16). At 30 mo, average exercise levels no longer differed significantly between groups (1390 and 1696 kcal/wk, respectively; P > 0.10). Participants sustaining high exercise levels (>2500 kcal/wk) for 30 mo had significantly (P < 0.001) greater 30-mo weight loss than did those exercising less (12 +/- 8.8 and 0.8 +/- 8.1 kg, respectively).

Conclusions: Although participants in the HPA group sustained the 2500-kcal activity goal during the 18-mo treatment, activity declined once treatment ended, which resulted in no between-group differences in activity or weight loss at 2.5 y. Participants who reported continuing to engage in high levels of exercise maintained a significantly larger weight loss.