Changes in Dietary Intake with Varying Doses of Physical Activity Within a Weight Loss Intervention: The Heart Health Study

Abstract

Abstract Objectives Successful weight loss interventions often require a multipronged approach. The need for interventions that incorporate both physical activity and dietary methodologies is apparent. The present study aimed to assess whether there were differential effects on dietary change within the context of a behavioral weight loss intervention that included different doses of physical activity. Methods Participants (N = 383; Age = 44.7 ± 8.2 years, BMI = 32.4 ± 3.8 kg/m2) were randomized to a reduced calorie diet (DIET, N = 127), diet plus a moderate dose of physical activity (MOD-EX, N = 129), or diet plus a high dose of physical activity (HIGH-EX, N = 127). All groups received weekly in-person intervention sessions for months 1–6, with combined in-person and telephonic sessions for months 7–12. Diet was prescribed at 1200–1800 kcal/day. MOD-EX was prescribed physical activity that progressed to 150 min/wk and HIGH-EX progressed to 250 min/wk. Physical activity, weight, and dietary intake were assessed. Dietary intake was assessed using the DHQII questionnaire. Results Retention at 12 months was 86.6% in DIET, 80.6% in MOD-EX, and 83.5% in HIGH-EX. Physical activity at 0 and 12 months was 65.4 ± 73.8 and 88.2 ± 104.3 min/wk in DIET; 68.7 ± 93.8 and 179.1 ± 125.3 min/wk in MOD-EX; and 71.5 ± 84.4 and 228.8 ± 148.3 min/wk in HIGH-EX (Group X Time P < 0.001). Weight decreased at 12 months (DIET: −9.9 ± 8.3 kg, MOD-EX: −10.8 ± 8.2 kg, HIGH-EX: −9.5 ± 7.3 kg) (P < 0.001), with no difference between groups. Energy intake decreased from baseline in all groups (6 mo: −495 ± 25.8 kcal/day, 12 mo: −502 ± 25.0 kcal/day) (P < 0.001). Percent dietary fat intake decreased (6 mo: −5.0 ± 0.4%, 12 mo: −3.8 ± 0.4%) (P < 0.001), whereas there was a non-significant increase in % carbohydrate intake (6 mo: 3.5 ± 0.4%, 12 mo: 3.0 ± 0.5%) and % protein intake (6 mo: 1.3 ± 0.2%, 12 mo: 1.0 ± 0.2%), with no difference between groups. Conclusions Weight loss was observed in all the interventions and physical activity did not enhance the weight loss that was observed. Also, the changes in diet that included reducing calories and fat intake were not impacted by the addition of physical activity. These findings have implications for interventions for weight loss in adults with obesity. Funding Sources National Institutes of Health.