The study, led by David Tilman of the University of Minnesota’s Department of Ecology, said the current trajectory of dietary patterns was leading to higher incidence of type 2 diabetes, cancer and heart disease, while also increasing land clearing and greenhouse gas (GHG) emissions.
“Although this pattern does not mean that healthier diets are necessarily more environmentally beneficial, nor that more environmentally beneficial diets are necessarily healthier, there are many alternative dietary options that should substantially improve both human and environmental health,” the researchers wrote.
They compared different dietary patterns for their health and environmental impacts, including Mediterranean, vegetarian, pescetarian (including fish and seafood, but not meat), and a projected income-dependent diet for 2050.
The income-dependent diet, when compared to the average global diet of 2009, was estimated to have 15% more calories and 11% more total protein. Based on projected incomes and current trajectories, the global diet in 2050 would have 61% more empty calories, 18% fewer servings of fruit and vegetables, 2.7% less plant protein, 23% more pork and poultry, 31% more ruminant meat, 58% more dairy and egg and 82% more fish and seafood, the researchers forecast.
Focus on health
Compared to the current average diet and the income-dependent 2050 diet, all three alternative diets were better for overall health. They all had higher consumption of fruits, vegetables, nuts and pulses and lower empty calorie and meat content.
Many of the world’s poorest people have inadequate diets, and would have better health if their diets provided more vitamins, minerals, essential fatty acids and protein, the researchers said. However, many people on moderate and high incomes have shifted their diets toward ones that cause health problems.
Vegetarian diets came out on top for reducing the risk of type 2 diabetes, by 41%, while the pescetarian diet cut risk by a quarter, and Mediterranean diets by 16%. Cancer risk was 7%-13% lower across the three diets, with pescetarians leading the way, followed by vegetarians and then the Mediterranean diet.
Meanwhile, Mediterranean diets cut heart disease risk the most (26%), closely followed by the pescetarian (21%) and vegetarian (20%) diets.
And the environment?
“All three alternative diets could reduce emissions from food production below those of the projected 2050 income-dependent diet, with per capita reductions being 30%, 45%and 55%for the Mediterranean, pescetarian and vegetarian diets, respectively,” the study’s authors wrote. “However, minimizing environmental impacts does not necessarily maximize human health.”
“Global diets link environmental sustainability and human health”
Authors: David Tilman & Michael Clark