Healthy People, Healthy Planet

Sustainable nutrition outlook NATURE SOPHIE CASSON FOR FOR SOPHIE CASSON Healthy people, healthy planet To provide 2050’s estimated 10 billion people with a healthy diet, global eating habits need to become more sustainable. By Chris Woolston very morsel of food from every plate, research. “We need to produce food groups them,” says Johan Rockström, an environmen- bowl and cooking pot around the that are good for health in ways that are restor- tal scientist at Stockholm University. In 2019, world takes a small bite from Earth’s ative to the planet, rather than extractive,” Rockström, Hawkes and other members of an resources. The human diet places says Corinna Hawkes, director of the Centre international group of scientists proposed the a strain on the environment, water for Food Policy at City, University of London. EAT-Lancet diet1, a global meal plan that could, Eresources, biodiversity and just about every The particular foods on the plate will vary from in theory, feed 2050’s estimated population of other measure of planetary health. With so one place to another, she says, but those meals 10 billion people (see ‘Planetary-health diet’). much at stake, researchers have turned their need to add up to something more sustainable That plan called for drastic cuts in meat con- attention to a pressing question: what sort of than society’s current fare. sumption and a much higher intake of fruits diet can the planet realistically support? “When you look carefully at the big sys- and vegetables. But it proved controversial The answer requires insights from fields tems that regulate the stability of our planet, with meat-industry proponents and econ- such as nutrition, agriculture and climate food is a dominant player in essentially all of omists, and the quest for a planetary diet S54 | Nature | Vol 588 | 10 December 2020 ©2020 Spri nger Nature Li mited. All ri ghts reserved. ©2020 Spri nger Nature Li mited. All ri ghts reserved. APHRC Elizabeth Kimani-Murage addresses community members at a meeting about food insecurity in Nairobi, Kenya. continues. When researchers and policy- meat consumption of high-income countries, about 200 g of fish and 200 g of white meat. makers convene at the United Nations Food Hawkes says. She notes that consuming a lot Controversially, the diet allows for just 100 g or Systems Summit in late 2021, a healthy-planet of red meat can raise the risk of cancer and so of red meat, around one and a half servings, diet will be near the top of the agenda. heart disease. “It’s not great for our health, per week. Rockström notes that’s a significant The goal will be a basic framework, not an and it’s not great for our planet,” she says. reduction from the roughly 700 g of red meat item-by-item menu, says Agnes Kalibata, a “There’s a strong alignment between health consumed each week by people in places such food-policy specialist in Kigali, Rwanda, who and sustainability.” as North America and Europe, but it’s much will be leading the summit as the UN special more than the amount typically eaten by peo- envoy. “Diets are influenced by cultures and “We have to rethink our ple in low-income countries. custom,” she says. “We can come up with the Despite its dire environmental impacts, meat principles of what a good diet will look like. We diets based on who are still has an important place in the global diet. need to find a balance.” the most vulnerable On a nutritional level, the proteins and minerals among us”. from animal products could be a real boost for Sustainability on a plate malnourished populations around the world, Most researchers agree that the current diet Hawkes says. “For infants who otherwise eat is not sustainable. A 2018 analysis2 estimated This convergence of nutrition and conser- rice or starchy cassava, meat is an incredibly that food production releases the equivalent vation is a central message of the EAT-Lancet efficient way of boosting micronutrient sta- of 13.7 gigatonnes of carbon dioxide in green- diet. The authors started by reviewing the tus,” she says. What’s more, she says, “meat has house gases into the air each year — more than best evidence for constructing a diet that tremendous cultural significance in people’s one-quarter of all human-caused greenhouse would optimize human health and reduce lives — it’s associated with high status”. gases. The same report estimated that agricul- the global toll of food-related health condi- tural irrigation accounts for about two-thirds tions, such as diabetes, heart disease, cancer Expensive gains of all fresh water used by humans. And about and obesity. The researchers didn’t even con- After investigating the potential environ- 37% of the planet’s land area, excluding deserts sider the impacts on climate or sustainability mental impacts of the EAT-Lancet diet, the and ice sheets, is already dedicated to food until the nutritional framework had been set, authors concluded that a nutritious diet for production. That footprint is likely to grow Rockström says. people could also be good for the planet. as the population increases. The EAT-Lancet commission ultimately pro- “We found that a healthy diet combined Some foods take up many more resources posed a ‘flexitarian’ diet that spans a spectrum with sustainable agricultural practices would than others. At the upper end, just 100 grams of food groups. It also suggested vegan and have positive impacts on biodiversity, land, of beef protein can result in the release of vegetarian options. Plants form the foun- water, nutrients and climate,” Rockström the equivalent of 105 kilograms of CO2. The dation of the commission’s flexitarian diet, says. The most significant improvements same amount of protein from a well-managed which recommends the daily consumption tied to a change in diet would come from a field of peas, by contrast, typically releases of 300 g of vegetables, 200 g of fruit, around reduction in phosphorus and nitrogen pol- the equivalent of only about 0.2 kg of CO2. 230 g of whole grains and 125 g of plant-based lution in waterways and greenhouse-gas These orders-of-magnitude differences protein-rich foods, such as lentils, nuts and dry emissions. The commission estimated that mean that any vision of a more sustainable beans. The diet calls for a mere five servings of the new meal plan could cut related green- diet has to include marked reductions in the animal protein per person per week, including house-gas emissions by about half — down to Nature | Vol 588 | 10 December 2020 | S55 ©2020 Spri nger Nature Li mited. All ri ghts reserved. ©2020 Spri nger Nature Li mited. All ri ghts reserved. Sustainable nutrition outlook PLANETARYHEALTH DIET would look much like the EAT-Lancet diet, but If every person had a daily food allocation to sustain not only their health but also that of the planet, what would it with a decidedly East African flavour. look like? The answer to this question in a study¹ from the EAT-Lancet commission, places an emphasis on plant-based The proposal from her institute is one of ten foods, and recommends an amount of animal-derived protein much lower than that eaten in high-income countries but much higher than the amount consumed in low-income countries. to make the finals of the Food System Vision Macronutrient intake (grams per day) Prize, a global contest sponsored by the Tubers or starchy Rockefeller Foundation in New York City. The Vegetables Whole grains Protein sources Fruit vegetables winners are due to be announced in Decem- 300 232 209 200 50 ber. Kimani-Murage says she wants Kenya to move away the sort of large-scale industrial Dairy foods Added fats farms that currently feed cities around the 250 52 world. “Food has been so commercialized or Added sugars commodified,” she says. “It’s produced for Legumes Nuts Poultry Fish Eggs 31 75 50 29 28 13 money and not for feeding people. We want to continue this local production of food even as the world urbanizes.” She notes that Beef, lamb and pork local food production could also significantly 14 reduce the costs of production and shipping, potentially increasing the affordability of an IMPACT OF UNUSED FOOD EAT-Lancet-style diet. Food loss (from post-harvest through the supply chain and up to, but not including, retail) and waste (at retail Feeding people at a local level is the key and consumption level) from the main food groups have negative environmental impacts. They all have a focus of the 2021 UN Food Systems Summit. blue-water (cubic metres of water wasted), carbon (tonnes of carbon dioxide equivalent omitted) and land (hectares of land used) footprint per tonne of food lost or wasted. The current global diet, Kalibata says, is unbal- anced, largely because of gaps in wealth and Cereals and pulses Fruits and vegetables Roots, tubers and oil-bearing crops Meat and animal products opportunity. In poor areas around the world, 9% people tend to fill their stomachs with starchy, 35% 44% Blue-water footprint carbohydrate-heavy food because they can’t afford other, more nutritious alternatives. “We Carbon footprint have to rethink our diets based on who are the Food loss and waste most vulnerable among us,” Kalibata says. She Land footprint says that high-quality proteins, whether meat- or plant-based, need to replace many of the 0 20 40 60 80 100 carbohydrates eaten in poorer areas. 13% Proportion (%) Kalibata thinks it will be possible to meet nutritional needs in the future, but it will take (BOTTOM) FAO 1 (TOP); REF.

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