Effect of Time-Based Strategies for Physical Activity on Weight Loss in Overweight Individuals

Abstract

Obesity is a major health problem in the United States due to the continued increase in prevalence rates. Physical activity is an important component for interventions because of its impact on enhancing weight loss and improving fitness. However, it is unclear if providing time-based strategies to enhance physical activity that compliment a standard behavioral weight loss program will improve weight loss and changes in cardiorespiratory fitness. PURPOSE: To evaluate effect of time-based behavioral strategies for physical activity on weight loss, physical activity, and cardiorespiratory fitness overweight individuals participating in a standard behavioral weight loss program. METHODS: Two-hundred and nineteen sedentary, overweight individuals (age = 42 ± 8.7 yrs; BMI = 33 ± 3.4 kg/m2) were randomized to one of three treatment groups. The standard behavioral weight loss intervention (SBWI) included reducing energy intake to 1200–1500 kcal/d, increasing exercise to 200 min/wk, and attending a weekly group session for 24 weeks and biweekly group sessions for the remainder of the 18-month intervention. The adoption group (ADOPT) received the SBWI intervention and also biweekly telephone contacts from weeks 1–12, and one weekly supervised exercise session and a pedometer campaign during months 0–6. The maintenance group (MAINT) received the SBWI intervention plus biweekly telephone contact from weeks 13–24, supervised exercise sessions during months 7–12, and a pedometer campaign during months 12–18. RESULTS: 146 of the subjects have completed the 18 month intervention with the remaining subjects still in the process of completing the intervention. Intention-to-treat analysis revealed a significant percent weight loss at 6 months of 7.3±7.8%, 8.2±6.3%, and 7.3±7.8% for ADOPT, MAINT, and SBWI, respectively (p<0.05), with no significant difference between groups. RESULTS: at 18 months revealed weight regain with percent weight loss from 0 to 18 months of 4.7±8.9%, 5.6±8.2%, and 2.7±5.0% for ADOPT, MAINT, and SBWI, respectively, with no significant difference between groups. CONCLUSIONS: Preliminary results indicate that behavioral strategies for physical activity added to a standard behavioral weight loss intervention did not improve weight loss at 6 or 18 months. Thus, the addition of time-based strategies that include telephone contact, supervised exercise, and pedometer campaigns that focus on physical activity do not appear to be justified compared to a standard behavioral weight loss. Therefore, additional intervention strategies should be examined to enhance long-term weight loss maintenance.