“You are what you eat.” We all know that a healthy diet is essential for good health and nutrition. But what if munching on nourishing foods not only improves your health, but also contributes to a healthier environment? This is exactly what a recent study found: a diet comprised mostly of whole grains, nuts, and vegetables can improve both human and planetary health. Whether you care about your own health or the environment—or better yet, both—choosing a diet for one cause also serves another. Pretty sweet deal, isn’t it?
The study, led by researchers at University of Oxford and University of Minnesota, examined the health and environmental impacts of commonly consumed foods. They tracked the dietary patterns and health outcomes of tens of millions of individuals of a wide variety of ethnicities, ages, and economic status. They examined the human health and environmental impacts of fifteen common food groups such as meats, legumes, vegetables, and fruits. They evaluated the human health outcomes of consuming these foods by measuring risks of type II diabetes, stroke, coronary heart disease, colorectal cancer, and mortality. The environmental impacts they examined include greenhouse gas emissions, land use, water use, and water pollution.
While many studies have looked at the human health and environmental impacts of certain foods and diets, very few have examined these two categories of impacts in connection with each other as this one. Such a unique analysis approach revealed fascinating correlation between these impacts.
On the positive side, foods associated with significant reductions in mortality also had a low environmental impact. For example, nuts, whole-grains, fruits, legumes, olive oil, and fish were found to be the healthiest food groups. All of these foods, except for fish, also had the lowest environmental impacts.
What’s more, foods that have a low environmental impact for one environmental indicator were often found to also have low impact for the other four environmental indicators. Compared to producing one kilogram of beef, for example, producing one kilogram of legumes requires less water and land, produces much less greenhouse gas emissions, and generates less pollution. Similarly, if a food improved one health outcome—like coronary heart disease—it was often associated with positive effects on other health outcomes.
At the other extreme, the environmental impacts of producing unprocessed and processed red meats had the greatest environmental impacts—10 to 100 times larger than those of plant-based foods. Consumption of red meat, especially processed red meat, is also associated with the highest health risks. This is no surprise. In 2015, the World Health Organization classified processed meat such as hot dogs, ham, sausages, and corned beef as carcinogenic and red meat as probably carcinogenic to humans.
As a plant-based dietary shift is recommended for both health and environmental reasons, this research underscores that the path towards improved public health and a more environmentally sustainable future depend fundamentally on the food we produce and consume. This insight aligns with recommendations from many other commissions and institutions, such as the EAT-Lancet Commission on Food, Planet, Health, World Resources Institute, and the FAO and the Food Climate Research Network. Without a global shift to more plant-based and plant-rich diets, we are unlikely to meet many of the United Nations Sustainable Development Goals and reduction in GHG emissions aligned with the Paris Agreement on climate change.
This large body of compelling evidence illuminating the urgency of a dietary shift, then, begs us to examine the fundamentals of our current food systems. How are incentives guiding consumers’ decisions concerning food consumption?
If the health and environmental consequences of consuming food are factored into the price of food—that is, if food price reflects not just the cost of production but the full cost of the human health and environmental impacts associated with its consumption—the worst foods would be the most expensive options and should cost more than they currently do.
Appropriate policies can encourage diets that are good for both our own health and the environment. In the meanwhile, we as consumers need to keep educating ourselves of the implications of our consumption and make informed decisions to the best of our ability. The priority in achieving the shared goals of human and planetary health can perhaps be best captured by seven words from famous American food writer Michael Pollan: “Eat food, not too much, mostly plants.”