What Does a Healthy, Sustainable Diet Look Like, According to Science?

sustainability-diet-lancet

The recommended diet would require doubling the consumption of  fruits, vegetables and legumes and cutting global consumption of red meat and added sugars by more than half. Photo credit: Facebook/EatStockholmFoodForum.

In both research and media coverage, questions about which foods are healthiest and which are the most sustainable are often asked in isolation. A report published on January 16 in top medical journal The Lancet is a significant exception.

“Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems” is a study that tackles the global issues of hunger, obesity and environmental degradation in concert, asking: How should people around the world eat to transform the food system in a way that will address all three?

“We’ve known about the connections between global warming, sustainability and healthy food production for a long time, but to have such a well-regarded journal with so much credibility make these recommendations is a really big deal,” says Natural Resources Defense Council food and agriculture policy specialist Sujatha Bergen. “It represents the consensus of the scientific and medical community.”

Nineteen “commissioners” and 18 co-authors from around the world—with varying expertise in fields like health, agriculture and environmental sustainability—were involved in the Eat-Lancet Commission, which was led by Walter Willett, MD, of Harvard T.H. Chan School of Public Health and Johan Rockstrom, PhD, of the Potsdam Institute for Climate Impact Research.

Before laying out the evidence for a healthy, sustainable diet, the authors argue that based on the evidence they compiled, current eating patterns and food production methods pose a massive global risk to people and the planet.

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Before laying out the evidence for a healthy, sustainable diet, the report’s authors argue that current eating patterns and food production methods pose a massive global risk to people and the planet. Graphic courtesy of The Lancet.

“The Commission shows that feeding 10 billion people a healthy diet within safe planetary boundaries for food production by 2050 is both possible and necessary,” they write. “It also demonstrates that the universal adoption of a planetary health diet would help avoid severe environmental degradation and prevent approximately 11 million human deaths annually.”

So what does a planetary health diet look like?

The recommended diet is high in plant-based foods like vegetables, fruits and whole grains and low in animal-based foods (especially red meat) and added sugars. It also emphasizes unsaturated fats over saturated fats. The authors refer to it as a “flexitarian” diet, in that it is largely plant-based but can include small amounts of meat, fish and dairy.

In other words, it looks a lot like a Mediterranean diet, which doesn’t seem that radical, except that to shift the entire population to this style of eating, it would require doubling the consumption of healthy foods like fruits, vegetables and legumes and cutting global consumption of red meat and added sugars by more than half.

The report outlines a plan to change the supply side of food production as well as five strategies—dubbed the “Great Food Transformation—to initiate the massive shifts proposed.” Graphics courtesy of The Lancet.

“It’s an aggressive target, but it’s recognition that we need big changes to make the impact that we need,” Bergen says. “We have seen the American diet change. As people learn more about the health impacts and the impacts on the planet of animal products, I think we’re going to continue to see change.”

The report goes on to outline a plan to change the supply side, suggesting scientific targets for reducing the environmental impact of food production, including variables like greenhouse gas emissions, water use and biodiversity loss. Finally, it outlines five strategies to initiate the massive shifts proposed—dubbed the “Great Food Transformation”—such as changing agricultural priorities from high volume to high nutrient-density and reducing food loss and waste.

“It is clear too that a Great Food Transformation will not occur without widespread multi-sector, multi-level action, which must be guided by scientific targets,” they write. “The data are both sufficient and strong enough to warrant immediate action. Delaying action will only increase the likelihood of serious, even disastrous, consequences.”

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