BACKGROUND:

The efficacy of physical activity with a healthful diet to reduce obesity is established; however, little is known about the translation of effective lifestyle strategies for obesity reduction in primary care settings.

METHODS:

We assessed the effectiveness of a 2-year behaviorally based physical activity and diet program implemented entirely within clinical practices to reduce obesity. A total of 490 sedentary, obese adults were randomized to usual care (n = 241) or to the behavioral intervention (n = 249). The usual care group received advice from their physicians about lifestyle as a strategy for obesity reduction. The behavioral intervention included individual counseling from health educators to promote physical activity with a healthful diet. The primary outcome was change in waist circumference (WC).

RESULTS:

A total of 396 participants completed the trial (80.8%). A significant main effect was observed for WC change within the intervention compared with usual care (P < .001) that was sustained at 24 months (mean [SE], -0.9 [0.4] vs 0.2 [0.4] cm; P = .05). Secondary analyses revealed significant main effects for change in WC in men (P = .009) and women (P = .02). In men, the mean (SE) reduction in WC at 24 months was greater with behavioral intervention compared with usual care (-1.6 [0.6] vs 0.1 [0.6] cm; P = .049). In women, the behavioral intervention was associated with differences in WC compared with usual care at 6 and 12 months (P ≤ .01) but not at 24 months (P = .10).

CONCLUSIONS:

Behavioral intervention in clinical settings is associated with modest reductions in WC during a 2-year study in obese patients. However, the effectiveness of the intervention is restricted to men.

TRIAL REGISTRATION:

clinicaltrials.gov Identifier: NCT00665158.