Greenhouse Gas Emissions of the U.S. Diet: Aligning Nutritional Recommendations with Environmental Concerns

Dietary choices – the overall food consumption patterns displayed by a population – can, and do, influence greenhouse gas emissions (GHGE) of the food system. Here, we consider the GHGE associated with production of the current U.S. diet, and various dietary recommendations. USDA’s loss adjusted food availability dataset is used to represent current consumption. GHG emission factors were compiled from published LCA sources. Production of the current U.S. diet has GHGE of 5.0 kg CO2eq capitaday, 28% of which is due to food losses; a diet based on USDA’s Dietary Guidelines has similar or greater GHGE as this current diet. Lacto-ovo vegetarian, vegan, and Harvard’s Healthy Eating Plate guidelines show 33%, 53%, and 33% lower GHGE, respectively, than their USDA omnivore counterpart. Official USDA food plans at four cost levels show increasing emissions with rising food costs, but decreasing emissions per unit cost. This paper suggests aligning environmental and health objectives through dietary recommendations policy.