Dietary choice is a key determinant of both health outcomes and environmental impacts. Human food systems play a key role in climate change, globally contributing about a quarter of all greenhouse gas emissions. Given the scale of both environmental and nutritional problems, solutions that could address both are desperately needed. Our research examines the interface between diet, health outcomes, and environmental impacts.
Triple Bottom Line: Carbon Footprint, Healthfulness, and Cost of Diets: In this study, we study the effects of simple dietary changes on three different outcomes: carbon footprint, healthfulness, and cost of diet. Using a nationally representative U.S. sample, we first identify who might be willing to change their diet if national dietary guidance where to include information about environmental sustainability. Then we calculate the outcomes if those people were to replace all or a portion of beef in their diets with chicken or meats with plant protein foods. We find that hypothetical replacements in a small percentage (16%) of individuals can modestly reduce the national food-related carbon footprint. Moreover, these substitutions can modestly improve diet quality and reduce diet costs for individuals who make changes.
Diet and Planetary Health. We presented a series of papers on the impacts of diet on climate and health outcomes at the American Society for Nutrition's 2019 annual conference. In one paper, we analyzed the impact that a single change in one's diet could have on the emission of greenhouse gases. A second paper outlined a method for analyzing health and environmental impacts from usual dietary intakes with data from only two 24-hour recalls on each individual. A third paper analyzed the greenhouse gas emissions and nutritional quality of vegan, "paleo," and other popular diets.
Carbon footprint of US diets. In this study, we analyze the carbon footprint of US diets and estimate how it relates to nutritional quality. To do this, we link data from the life cycle assessment literature on the greenhouse gas emissions from food production to nationally representative diets reported in the National Health and Nutrition Examination Survey. We find that diets with the lowest-impacts are healthier overall than those with the highest impacts.
SNEB position paper. Improving the nutritional health of a population is a long-term goal that requires ensuring the long-term sustainability of the food system. In this position paper of the Society for Nutrition Education and Behavior, we argue that environmental sustainability should be inherent to dietary guidance. We discuss current environmental trends, how they threaten long-term food security, and how dietary choices can help address the problem.
Comment on reducing meat demand. Although substantial evidence indicates that consuming less meat could significantly reduce the effects of our food system on the environment, we know much less about how to achieve this goal. In this commentary, we discuss a recent review of the literature on changing physical microenvironments to reduce meat demand.
Environmental impacts of US diets. To estimate the impact of US dietary choices on greenhouse gas emissions and energy demand we built a food impacts database from an exhaustive review of the life cycle assessment literature and linked it to as-consumed foods reported in the National Health and Nutrition Examination Survey. Our results allow us to estimate a distribution of impacts from self-selected diets in the US. The top 20% of diets accounted for about 8 times the emissions as the bottom 20% of diets.
Webinar on environmental sustainability and dietary guidance. The Nutrition Resource Centre of the Ontario Public Health Association organized a webinar to explore the relationship between individual food choices and environmental impacts, summarize recommendations for integrating environmental sustainability in dietary guidance, outline international best practices for this integration, and discuss this in the context of Canada's new food guide.
Webinar on carbon footprint of US diets. This webinar – sponsored by the American Public Health Association, the Tulane Center for Excellence in Maternal and Child Health, and the Tulane Prevention Research Center – explains our methods on the calculation of carbon footprints for specific foods and diets and the results from our research.
APHA abstracts on our research on diet and greenhouse gases. In 2017, the American Public Health Association's annual meeting focused on the theme, "Creating the Healthiest Nation: Climate Changes Health." We organized a theme-related session on our research linking diet to climate change, in which we presented 4 papers. The abstracts are available below.