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.

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.

Three high schools in a diverse, Northeast US urban district with universally free meals.

High-school students participating in the NSLP.

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.

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.

To determine if US household food purchases with lower levels of red meat spending generate lower life-cycle greenhouse gas emissions (GHGE), greater nutritional quality and improved alignment with the Dietary Guidelines for Americans. Affordability of purchasing patterns by red meat spending levels was also assessed.

Household food purchase and acquisition data were linked to an environmentally extended input–output life-cycle assessment model to calculate food GHGE. Households (n 4706) were assigned to quintiles by the share of weekly food spending on red meat. Average weekly kilojoule-adjusted GHGE, total food spending, nutrients purchased and 2010 Healthy Eating Index (HEI-2010) were evaluated using ANOVA and linear regression.

USA.

Households participating in the 2012–2013 National Household Food Acquisition and Purchase Survey.

There was substantial variation in the share of the household food budget spent on red meat and total spending on red meat. The association between red meat spending share and total food spending was mixed. Lower red meat spending share was mostly advantageous from a nutritional perspective. Average GHGE were significantly lower and HEI-2010 scores were significantly higher for households spending the least on red meat as a share of total food spending.

Only very low levels of red meat spending as a share of total food spending had advantages for food affordability, lower GHGE, nutrients purchased and diet quality. Further studies assessing changes in GHGE and other environmental burdens, using more sophisticated analytical techniques and accounting for substitution towards non-red meat animal proteins, are needed.