Evaluate the feasibility, fidelity and preliminary efficacy of Camp NERF to prevent unhealthy weight gain and promote healthy behaviours in children during the summer.

Camp NERF was an 8-week, multicomponent, theory-based programme coupled with the US Department of Agriculture’s Summer Food Service Program. Twelve eligible elementary-school sites were randomized to one of three treatment groups: (i) Active Control (non-nutrition, -physical activity (PA), -mental health); (ii) Standard Care (nutrition and PA); or (iii) Enhanced Care (nutrition and PA, plus cognitive behavioural techniques) programming. Efficacy was determined by assessing mean change by group in child outcomes using hierarchical linear regression models.

Low-income, urban neighbourhoods in Columbus, OH, USA.

Economically disadvantaged, racial minority children of elementary school age (kindergarten–5th grade).

Eighty-seven child–caregiver dyads consented; eighty-one completed pre- and post-intervention assessments resulting in a 93·10 % retention rate. Delivery of the intended lesson occurred 79–90 % of the time. Of the children, 56·98 % (n 49) were female; 89·53 % (n 77) were Black. Overall mean change in BMI Z-score from baseline to post-intervention was −0·03 (se 0·05); change in BMI Z-score did not differ significantly between treatment group. Change in nutrition, PA, mental health or psychosocial outcomes did not differ between groups.

Results from the current study demonstrate feasibility and fidelity, yet no intervention effect of Camp NERF. Instead, findings suggest that participation in structured programming of any type (health behaviour-related or not) may prevent unhealthy summer weight gain. Additional studies are needed to confirm findings. Results have implications for child nutrition policy addressing the issue of summer health.