A Randomized Controlled Trial of Students for Nutrition and eXercise

Objectives: We conducted a randomized controlled trial (RCT) of Students for Nutrition and eXercise (SNaX), a middle-school-based obesity-prevention intervention combining school-wide environmental changes, multimedia, encouragement to eat healthy school cafeteria foods, and peer-led education and marketing. Methods: We randomly selected schools from the Los Angeles Unified School District (LAUSD) and assigned five to the intervention group and five to a wait-list control group. School records were obtained for number of fruits and vegetables served, students served lunch, and snacks sold per attending student. Pre- and post-intervention surveys assessed psychosocial variables among 2,997 seventh-graders (75% of all seventh-graders across schools). Hypotheses: For the RCT of SNaX, we hypothesized that SNaX would lead to increases in the proportion of students served in the cafeteria (because SNaX markets cafeterias' healthy foods); increased fruit and vegetable servings (because SNaX increases access to sliced/bite-sized fruits and vegetables); decreased school store snack sales; and greater water consumption. We also hypothesized that SNaX would lead to more positive attitudes about the cafeteria and water, improve obesity-prevention knowledge, and increase intentions to drink water.