Food Substitution and Waste Reduction Can Reduce the Environmental Impacts and Food Costs of School Meal Programs in the United States: An 2011-2018 NHANES Analysis.

Background: US school meal programs serve billions of meals annually; however, little is known about their environmental impacts.

Objective: This study estimated the daily greenhouse gas emissions (GHGE), water scarcity footprint (WSF), and food cost associated with food consumed in the National School Lunch Program and School Breakfast Program, and modeled the association of food substitutions and food waste reduction.

Design: A cross-sectional analysis of Day-1 dietary intake in the National Health and Nutrition Examination Survey, 2011-2018. A diet model was constructed to estimate the effects of food substitutions and food waste reduction on GHGE, WSF, food cost, and nutrient intake.

Participants/setting: Participants included 796 children and adolescents from prekindergarten to grade 12 who consumed breakfast or lunch on a weekday from a school cafeteria that met the minimum standard for an eligible meal (ie, offered or served minimum amounts of milk, protein foods, whole grains, fruits, and/or vegetables), and that is reimbursed for food costs.

Main outcome measures: The main outcomes were per capita nutrient intake, GHGE, WSF, and food cost.

Statistical analyses performed: Differences in mean influences and between actual consumption and 2 modeled scenarios (food substitutions and food waste reductions) were evaluated using paired Wald tests. The modeled food substitutions were soy milk for cow's milk, plant-based meat alternatives for beef, poultry for beef, and seafood for beef. All values in the figures were adjusted for energy and survey cycle using linear regression models.

Results: Daily per capita GHGE and WSF for food consumed in school food programs were 1.69 kg carbon dioxide equivalents (95% CI 1.55-1.84) and 1023 L equivalents (95% CI 920-1127), respectively. Dairy (mainly cow's milk) and protein foods (mainly beef) were the largest contributors to GHGE. Fruit was the largest contributor to the WSF. Modeled food substitutions significantly reduced GHGE by 14% to 25% and WSF by 11% to 14% for the school meal programs; however, there were mixed effects on food cost (-2% to 6% change) and nutrient intake. Modeled food waste reductions of 5% were associated with a 1% decrease in GHGE, WSF, and food costs.

Conclusions: The National School Lunch Program and School Breakfast Program are critical to child nutrition, and food substitution and food waste reduction strategies may lower their environmental footprint with manageable influences on nutrient density, although implementing these programs effectively can be challenging.