Objective physical activity and weight loss in adults: the step-up randomized clinical trial.

Abstract

To examine the amount of objectively measured MVPA and LPA that is associated with long-term weight loss and the maintenance of clinically significant weight loss. Adults (N = 260; BMI: 25 to <40 kg/m(2) ; age: 18-55 years) participated in an 18-month behavioral weight loss intervention and were prescribed a low-calorie diet and increased physical activity. Change in weight and objectively measured physical activity were assessed. MVPA > 10 (MET-min/week) was computed from bouts >10 min and >3.0 METs and MVPA < 10 was computed from bouts <10 min in duration and >3.0 METs. LPA was computed from bouts between 1.5 to <3.0 METs. When grouped on percent weight loss at 18 months, there was a significant group × time interaction effect (P < 0.0001) for both MVPA > 10 and LPA, with both measures being significantly greater at 18 months in those with >10% weight loss. Similar results were observed for MVPA > 10 and LPA with participants grouped on achieving >10% weight loss at 6 months and sustaining this at 18 months. MVPA > 10 of 200-300 min per week, coupled with increased amounts of LPA, are associated with improved long-term weight loss. Interventions should promote engagement in these amounts and types of physical activity.