Abstract
OBJECTIVE: To compare federally reimbursable school meals served when competitive foods are removed and when marketing and nudging strategies are used in school cafeterias operating the National School Lunch Program (NSLP). The second objective was to determine how marketing and nudging strategies influence competitive food sales. DESIGN: In the Healthy Choices School, all competitive foods were removed; the Healthy Nudging School retained competitive foods and promoted the school meal programme using marketing and nudging strategies; a third school made no changes. Cafeteria register data were collected from the beginning of the 2013-2014 school year through the four-week intervention. Outcome measures included daily entrées served; share of entrées served with vegetables, fruit and milk; and total competitive food sales. Difference-in-difference models were used to examine outcome measure changes. SETTING: Three high schools in a diverse, Northeast US urban district with universally free meals. PARTICIPANTS: High-school students participating in the NSLP. RESULTS: During the intervention weeks, the average number of entrées served daily was significantly higher in the Healthy Choices School (82·1 (se 33·9)) and the Healthy Nudging School (107·4 (se 28·2)) compared with the control school. The only significant change in meal component selection was a 6 % (se 0·02) higher rate of vegetable servings in the Healthy Choices School compared with the control school. Healthy Nudging School competitive food sales did not change. CONCLUSIONS: Both strategies - removing competitive foods and marketing and nudging - may increase school meal participation. There was no evidence that promoting school meals decreased competitive food sales.