Predictors of Sustained Reduction in Energy and Fat Intake in the Diabetes Prevention Program Outcomes Study Intensive Lifestyle Intervention

Background: Few lifestyle intervention studies examine long-term sustainability of dietary changes. Objective: To describe sustainability of dietary changes over 9 years in the Diabetes Prevention Program and its outcomes study, the Diabetes Prevention Program Outcomes Study, among participants receiving the intensive lifestyle intervention. Design: One thousand seventy-nine participants were enrolled in the intensive lifestyle intervention arm of the Diabetes Prevention Program; 910 continued participation in the Diabetes Prevention Program Outcomes Study. Fat and energy intake derived from food frequency questionnaires at baseline and post-randomization Years 1 and 9 were examined. Parsimonious models determined whether baseline characteristics and intensive lifestyle intervention session participation predicted sustainability. Results: Self-reported energy intake was reduced from a median of 1,876 kcal/day (interquartile range [IQR]=1,452 to 2,549 kcal/day) at baseline to 1,520 kcal/day (IQR=1,192 to 1,986 kcal/day) at Year 1, and 1,560 kcal/day (IQR=1,223 to 2,026 kcal/day) at Year 9. Dietary fat was reduced from a median of 70.4 g (IQR=49.3 to 102.5 g) to 45 g (IQR=32.2 to 63.8 g) at Year 1 and increased to 61.0 g (IQR=44.6 to 82.7 g) at Year 9. Percent energy from fat was reduced from a median of 34.4% (IQR=29.6% to 38.5%) to 27.1% (IQR=23.1% to 31.5%) at Year 1 but increased to 35.3% (IQR=29.7% to 40.2%) at Year 9. Lower baseline energy intake and Year 1 dietary reduction predicted lower energy and fat gram intake at Year 9. Higher leisure physical activity predicted lower fat gram intake but not energy intake. Conclusions: Intensive lifestyle intervention can result in reductions in total energy intake for up to 9 years. Initial success in achieving reductions in fat and energy intake and success in attaining activity goals appear to predict long-term success at maintaining changes.