The Impacts of Dietary Change on Greenhouse Gas Emissions, Land Use, Water Use, and Health: A Systematic Review

Abstract

Food production is a major driver of greenhouse gas (GHG) emissions, water and land use, and dietary risk factors are contributors to non-communicable diseases. Shifts in dietary patterns can therefore potentially provide benefits for both the environment and health. However, there is uncertainty about the magnitude of these impacts, and the dietary changes necessary to achieve them. We systematically review the evidence on changes in GHG emissions, land use, and water use, from shifting current dietary intakes to environmentally sustainable dietary patterns. We find 14 common sustainable dietary patterns across reviewed studies, with reductions as high as 70-80% of GHG emissions and land use, and 50% of water use (with medians of about 20-30% for these indicators across all studies) possible by adopting sustainable dietary patterns. Reductions in environmental footprints were generally proportional to the magnitude of animal-based food restriction. Dietary shifts also yielded modest benefits in all-cause mortality risk. Our review reveals that environmental and health benefits are possible by shifting current Western diets to a variety of more sustainable dietary patterns.

Fig 1. Selection of eligible studies.

Fig 2. Relative differences in GHG emissions (kg CO₂eq/capita/year) between current average diets and sustainable dietary patterns.

Note: n = number of studies, mdn = median.

Fig 3. Relative differences in land use (m²/capita/year) between current average diets and sustainable dietary patterns.

Note: n = number of studies, mdn = median.

Fig 4. Relative differences in water use (L/capita/day) between current average diets and sustainable dietary patterns.

Note: n = number of studies, mdn = median. The lower and upper bounds of the boxes represent the 1^st and 3^rd quartiles, respectively, and the line within is the median. Whiskers show the minimum and maximum range, excluding outliers, which are shown as dots, and represent values more than 1.5 times the 1^st and 3^rd quartiles.