One-Year Follow-Up of Weight Trajectories After the EDDY School-Based Nutrition and Physical Activity Program

Background/Objectives: The Effect of Diet and Exercise Training on Obesity and Secondary Disease Prevention and on the Lifestyle of Young Children (EDDY) study implemented a two-year school-based nutrition and physical activity program in a Viennese primary school to promote healthy weight trajectories. This follow-up examined whether anthropometric benefits persisted one year after program cessation without active intervention. Methods: Prospective longitudinal data from 36 intervention-group children (76.6% completion rate from baseline n = 47) were analyzed. Standardized measurements at baseline (T1), post-intervention (T2), and one-year post-intervention (T3) included BMI, SDS-BMI, and waist-to-height ratio by trained staff. Mixed-effects models evaluated changes over time with time, sex, baseline age, and baseline anthropometry as fixed effects. Results: At T3, median age was 10.5 years (IQR: 10.2–11.0). BMI increased consistently with normal growth (time effect p = 0.112), with a mean post-intervention increase of 0.70 kg/m2 (95% CI: 0.41–0.99; p < 0.001). SDS-BMI remained stable across periods (time effect p = 0.967; post-intervention change +0.013 SDS units, 95% CI: −0.178 to 0.109; p = 0.826). Waist-to-height ratio showed small changes (time effect p = 0.041) modified by baseline values, remaining within normal range. No sex-by-time interactions were observed (all p > 0.13). Conclusions: One year post-EDDY intervention, participating children maintained stable SDS-BMI and waist-to-height trajectories, reflecting sustained healthy growth. These results highlight the feasibility of maintaining healthy weight trajectories after the EDDY school-based nutrition and physical activity program and underscore the need for larger controlled trials to establish the long-term effectiveness of school-based programs.