The 2019 EAT-Lancet Commission report focused on identifying a planetary health diet for the projected 2050 population of ten billion people. This seminal report was presented in more detail in the previously prepared online module for the Updates on Nutrition series as part of the Growth through Nutrition Online Training program. The EAT- Lancet report emphasizes a diet that addresses human health and planetary health simultaneously.
Globally and in North America, people are over consuming red meat, starchy vegetables, eggs, and
poultry. In Sub Saharan Africa, it is only starchy vegetables that are over consumed; this is not surprising given that diets in this region are dominated by maize, wheat and/or rice. What is clear is that overall, no region is immune from unhealthy diets; the world is not eating enough of nutritious foods that make up a healthy diet, including fruits and vegetables, legumes and nuts and seeds.
One of the major constraints to achieving the EAT Lancet Commission reference diet is the cost of healthy eating. The nature of the global food supply is such that calories are cheap, whereas nutrients are not. Globally, calories from staple grain crops, maize, wheat, and rice and those from sugar cane tend to be inexpensive, whereas the recommended nutrient-rich foods (fruits, vegetables, animal source food-ASF) generally cost more. In low and middle-income countries (LMIC), the nutrition transition drives the dietary shift from grains and tubers toward more varied diets with more animal protein but also more processed foods with added sugars and fats. In high income countries (HIC), it is lower income groups that consume energy-dense diets of low nutritional value. The consumption of nutrient-rich whole grains, low-fat dairy, lean meats, and fresh produce rises with education and incomes.
The EAT-Lancet healthy reference diet is an important step in advancing our knowledge of a healthy diet. While the EAT-Lancet healthy reference diet provided a road map of an optimal dietary pattern to promote health, their analysis did not include cost to achieve this type of diet; several recent studies, published since the EAT Lancet series was published, have found that the cost of this diet is unreachable for 1.6 billion people (see references below). The analysis from these two more recent studies shows that healthy eating is not cost free. Nutrient dense diets, on average, cost more. Unless strategies can be developed to decrease the cost of healthy foods at the margin, the planetary reference diet will be beyond the reach of the many vulnerable consumers.
The EAT reference diet also presents serious dilemmas for widespread adoption, and the increases in agricultural production that will be required are challenging. The feasibility of these production changes needs to be considered within the context of current national agricultural systems and how and if these strategies will or can be adapted to achieve agricultural production targets. For example, the reference diet would require a > 150% increase in nut production. These production goals are unrealistic, at least in the short run, for most countries.
There will likely be tradeoffs between environmental goals versus nutritional goals. For example, ASF are a rich source of high-quality protein and a range of micronutrients; there are, however, tradeoffs between sustainable agricultural techniques and the amount of ASF in dietary patterns. While the potential contribution of ASF in meeting nutritional needs is incontrovertible, controversies about the role of ASF include implications for health, and sustainability. With specific regard to the latter, the primary issue is around the relative contribution of animal agriculture to green-house gas emissions, primarily methane. The relative net impact of ASF in comparison to the nutritional output is not settled science and is complicated by our understanding of net greenhouse gas (GHG) accumulation, resource depletion, and the trade-off of efficiently meeting nutritional needs while exploiting land resources that would otherwise not be available for food production. Fully understanding the impacts of food production systems such as ASF requires integrated modeling techniques such as Life Cycle Analysis.
The challenges between nutritional, agricultural and environmental goals may seem daunting. The current emphasis on multidisciplinary approaches to healthy eating is addressing these complexities and should lead to guidance on evidence-based policies that balance issues of a healthy diet that is sustainable and respectful of natural resources.
References
Hirvonen K, Bai Y, Headey D, Masters, W. Affordability of the EAT-Lancet Reference Diet: A Global
Analysis. 2019. Available at: https://doi.org/10.1016/S2214-109X(19)30447-4.
Drewnowski A. Analyzing the Affordability of the EAT Lancet Diet. Lancet Global Health. 2020. Available at: https://doi.org/10.1016/S2214-109X(19)30502-9.
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Eileen Kennedy is a former dean of Tufts Friedman School of Nutrition Science and Policy. Currently a professor at the School, her research interests include assessing the health, nutrition, diet and food security impacts of policies and programs; nutrient density and diet diversity; and agriculture nutrition linkages. She is a member of the High Level Panel of Experts on Food Security and Nutrition of the UN Committee on World Food Security, as well as the World Economic Forum's Global Council on Food Security and Nutrition.
