LAUSR

Objectives To understand potential climate implications of dietary patterns associated with commercial weight loss diets, we tested the hypothesis that different consumption patterns of six commercial weight loss diets would shift United States greenhouse gas emissions (GHGE) if followed on a large scale. Methods An estimated 50-70% of adults are interested in controlling their weight with diets, many advocating lower carbohydrate, higher fat and higher animal protein intake. While considerable research exists on the environmental and greenhouse gas emissions (GHGE) implications of dietary patterns, no identified work has focused similarly on weight loss diets. Atkins, Biggest Loser, DASH, Weight Watchers, Keto and Whole30 diets were selected for this study based on consumer visibility, market share, and documented efficacy. Official 1-week sample plans were collected to create representative samples of each diet and converted to unprocessed primary equivalents. Cradle-to-farm gate GHGEs for individual food items were adapted from FAO's Global Livestock Environmental Assessment Model and 732 data points from 115 life cycle assessment studies. Results Estimated GHGEs varied significantly across the diet meal plans. Whole30 and showed the highest GHGEs per capita, while Keto, Biggest Loser and Atkins were lower but over twice that of DASH and Weight Watchers, which had the lowest. The largest single category value for each diet was bovine meat, suggesting that lowering recommendations for consumption of bovine meat could significantly decrease the GHGEs of each diet. Conclusions Our results provide a better understanding of potential costs and benefits associated with dietary recommendations for weight loss, critical to identifying impactful opportunities to shift dietary patterns toward public health and ecological goals, particularly reducing meat and increasing consumption of vegetables and pulses. Funding Sources Support provided by the Johns Hopkins Center for a Livable Future (CLF) with a gift from the GRACE Communications Foundation.