Co-designing food systems for nutrition and the environment
The way we produce food is the single most significant way humanity modifies the environment. Charles Godfray examines to what degree we need to consider the joint nutrition and environmental consequences of changes to food system policy.
Changing food systems such that they address the needs of the 800 million people who go to bed hungry each night and help tackle the epidemic of obesity (nearly two billion people around the world are overweight or obese) is an enormous and pressing challenge. As part of the work of the Global Panel on Agriculture and Food Systems for Nutrition an initiative has been set up to answer the question “What decisions do policy makers need to take in the coming decades to ensure that food systems deliver high quality diets that are accessible in low and middle income countries by 2035, particularly for women and children?”. Lawrence Haddad, who blogged recently about moving towards nutrition-friendly food systems, is chairing a Lead Expert Group leading this initiative, and I’m very pleased to be one of its members.
An issue that we are trying to get to grips with is the degree to which we need to consider the joint nutrition and environmental consequences of changes to food system policy. Not only is food one of the most important determinants of human health, the way in which we produce food is the single most significant way humanity modifies the environment. Agriculture occupies a very large fraction of the land that isn’t frozen or desert and fishing has modified many aquatic ecosystems. More of the freshwater resources that are available to people are used in food production than for any other purpose and the excess fertilisers and other chemicals that leach from farmland greatly pollute many water bodies and seas. Roughly 30% of greenhouse gas emissions come from the food system, divided approximately equal between emissions from land conversion and from current agriculture. Preventing further deforestation and land conversion will be critical to maintaining increases in global temperature within manageable bounds and this means ensuring our existing agriculture footprint can supply future food demands. Stemming the loss of biodiversity also requires halting land conversion and producing food in ways that have less impact on the natural environment.
So to what degree are better nutrition and better environments a separate agenda? Where are there synergies and where are their trade-offs? The good news is that some policies will have very clear joint benefits. Policies designed to persuade people not to eat excessive amounts of red meat have clear nutritional health benefits and, other things being equal, reduce the impact of agriculture on the environment. The latter is true because a majority of global livestock is fed on grain and it takes more land to produce the same amount of calories as meat compared with bread or human food made from other grains. Meat production is also typically thirsty and has driven much deforestation. It is no surprise that the World Wildlife Fund has been particular active in asking what a healthy and sustainable diet might look like – see for example their Livewell Plate initiative.
The insertion of “other things being equal” in the previous paragraph hides an enormous amount of complexity. There are many different types of meat, and many different production systems, and not all have the same environmental and health consequences. Tara Garnett and colleagues have written a very interesting article exploring some of these issues on the Food Climate Research Network website. Tara will be contributing to the work of our Lead Expert Group as we grapple with these issues.
Might there be trade-offs? Consider the issue of nitrogen fertilisers leaching from farmland and polluting drinking water and the broader environment. One way to reduce this problem would be to increase nutrient recycling and use less artificial fertiliser (whose synthesis also entails the release of much greenhouse gases) and use more animal and indeed human waste. A more circular nitrogen economy would have great environmental benefits but if done badly might negatively affect nutrition. One reason that India has made slower progress on nutrition than China is that the take up of modern sanitation has been much slower leading to more of the gastrointestinal diseases that can impair nutrition. If more use of animal and human manure was done in a way that increased disease transmission than the positive environmental benefits would come with a negative nutrition trade off.
We are not the only group grappling with this issue. Every five years the US produces Dietary Guidelines for Americans and the latest release is due this year. In February the U.S. Dietary Guidelines Advisory Committee suggested the Guidelines should take into account issues of sustainability. This has led to an intense political debate with accusations of mission creep and pandering to vested interests, and questions whether Congress will mandate the agencies responsible* to only include health and not sustainability criteria. A policy forum article in Science by Kathleen Merrigan and colleagues explores this issue further and in my view makes a good argument for the broader approach.