Objective Physical Activity and Weight Loss in Adults: The Step-Up Randomized Clinical Trial

OBJECTIVE: 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. DESIGN AND METHODS: Adults (N=260; BMI: 25 to <40 kg/m(2); age: 18–55 years) participated in an 18month 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 (METmin/wk) was computed from bouts ≥10 minutes and ≥3.0 METS and MVPA<10 was computed from bouts <10 minutes in duration and ≥3.0 METS. LPA was computed from bouts between 1.5 to <3.0 METS. RESULTS: When grouped on percent weight loss at 18 months, there was a significant Group X 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. CONCLUSIONS: MVPA>10 of 200 to 300 minutes 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.