There is widespread interest in dietary strategies that lower environmental impacts. However, various forms of malnutrition are also widely prevalent. In a first study of its kind, we quantify the water-scarcity footprint and diet quality score of a large (>9000) population of self-selected adult daily diets. Here, we show that excessive consumption of discretionary foods—i.e., energy-dense and nutrient-poor foods high in saturated fat, added sugars and salt, and alcohol—contributes up to 36% of the water-scarcity impacts and is the primary factor differentiating healthier diets with lower water-scarcity footprint from poorer quality diets with higher water-scarcity footprint. For core food groups (fruits, vegetables, etc.), large differences in water-scarcity footprint existed between individual foods, making difficult the amendment of dietary guidelines for water-scarcity impact reduction. Very large reductions in dietary water-scarcity footprint are possible, but likely best achieved though technological change, product reformulation and procurement strategies in the agricultural and food industries.

Food systems vitally depend on croplands, which are a scarce natural resource. Croplands are also heterogeneous, differing in productive capability and in environmental context. Some are in regions of high biodiversity conservation importance, others in regions vulnerable to food insecurity. In this study, life cycle assessment was used to quantify cropland scarcity footprints, cropland biodiversity footprints and cropland malnutrition footprints for 9341 individual Australian adult daily diets. Dietary cropland scarcity footprints averaged 7.1 m²yr-e person⁻¹ day⁻¹, exceeding a target of 6.1 m²yr-e person⁻¹ day⁻¹, consistent with the proposed global cropland planetary boundary of 15% of the ice-free land area. Discretionary foods, which are energy-dense and nutrient-poor foods high in saturated fat, added sugars and salt, and alcohol and are not essential to a healthy diet, made the largest contribution, followed by fresh meats and alternatives, breads and cereals, fruit, dairy and alternatives and vegetables. Around 45% of the variation in cropland footprint between individuals was explained by differences in total dietary energy intake. Diets characterised by higher diet quality and lower cropland scarcity footprint required only 4.2 m²yr-e person⁻¹ day⁻¹ and recommended diets based on the food choices of this subgroup required 5.9 m²yr-e person⁻¹ day⁻¹. Eating within the global cropland planetary boundary appears realistic if Australians greatly reduce their intake of discretionary foods and moderate their food choices within the “meat and alternatives” food group.

This systematic review examined the effectiveness of interventions of school-based nutrition education programs that included environmental sustainability components in addressing fruit and vegetable (F&V) consumption and/or variety among children (aged 5-12 years). The systematic search included MEDLINE, CINAHL, ERIC, Global Health, PsychINFO, EMBASE, the Cochrane Library, and 3 clinical trial registries. Searches between January 1, 1987, and February 22, 2022, found 18 eligible studies. The Evidence Project risk-of-bias (RoB) tool was used for quality assessment. Sixteen studies had moderate-to-high RoB, and 2 had low RoB. Eight studies reported significant increases in F&V consumption and/or variety. Programs that included environmental sustainability experiential components (i.e., gardening, tasting F&Vs, and cooking activities) and were underpinned by a theoretical framework were more likely to report significant outcomes than studies that reported no effects. This review underscores the benefits of school-based nutrition education programs that incorporate experiential components of environmental sustainability. These findings could support future researchers in designing strategies to improve children's F&V consumption by incorporating the experiential components of environmental sustainability into nutrition programs. In addition, conducting process evaluations to gather teachers' input to overcome common implementation barriers, performing long-term follow-up assessments to monitor behavioral changes over time, and implementing school policies to support these programs could also be beneficial. This review was registered with the International Prospective Register of Systematic Reviews (CRD42020184727).