Can your diet be more sustainable?

Jeanne O'Rourke | March 28, 2019 | Newsletters

Andy Whitman

Director, Sustainable Economies

Why would a sustainability organization like Manomet be interested in human diet and nutrition? As it turns out, what we eat may profoundly affect our world and the next generation. Agriculture is the world’s largest industry and employs more than one billion people and generates over $1.3 trillion of food annually. To feed our current population, it takes about 50 percent of the Earth’s habitable land. And the planet will be home to another 2 billion people by 2050. What we eat is one of the most important sustainability issues of our day.

The buzz words of today are ‘sustainable diets’ and ‘sustainable nutrition.’ If you think it sounds complicated, it is, at least in how the UN Food and Agriculture Organization (FAO) defines sustainable diets: “Sustainable diets are protective and respectful of biodiversity and ecosystems, culturally acceptable, accessible, economically fair and affordable, nutritionally adequate, safe, and healthy, while optimizing natural and human resources[1].”

Sustainable nutrition has been heralded as one of a few key solutions to our food sustainability challenge. It suggests we need to not only to change our farming practices on the ground, as Manomet promotes by working with agricultural partners across the U.S., but also change what we eat.

To feed our current population, it takes about 50 percent of the Earth’s habitable land.

Because over 44% of food waste occurs at home, we might diminish our environmental footprint best by starting with reducing food waste.

If Americans replaced all incandescent bulbs with EnergyStar bulbs, there would be a 1.2% GHG savings. If all Americans went “meatless” for one day a week, there would be just 0.6% GHG savings.

But a sustainable diet is also about human health. We live on a planet where many people are malnourished, under- or over-fed: approximately 462 million adults worldwide are underweight, while 1.9 billion are either overweight or obese[1]. The science and the medical community in the US has promoted eating less red meat, fats, and sugar, and eating more fruits and vegetables for health reasons. Recent research on diet and the microbes in our digestive system indicate that diet can even impact our mental health and performance[2].

The notion of sustainable diets is not new news. Back in 1971, Francis Moore Lappé produced a bestselling book: Diet for a Small Planet. It promoted a largely vegetarian diet that relied heavily on plant-based proteins to achieve a nutritious diet. It was based on the notion was that meat production was the problem and a big environmental threat. Without meat production, Lappé argued that our world would be more sustainable.

However, I encourage anyone diving into this topic to be cautious, as industry groups and individuals have much at stake and bring a lot of their values to the table. Large traditional companies in animal agriculture promote animal proteins while investors and start-ups are promoting the “virtues” of new products like oat milk and laboratory meat. Almost everyone has significant financial capital at stake.

The issue of sustainable diet has had renewed interest with the recent EAT-Lancet Commission report[3] and a flurry of scientific papers in noteworthy journals, which make claims similar to Lappé’s original claim that reducing or eliminating all animal protein from our diets, including red meat, poultry, eggs, and dairy, is good for our health and the planet.

Some of these reports such as the EAT-Lancet Commission report promote the near elimination of animal protein from our diets. These reports rely on some sources of discredited data or make assumptions that don’t entirely fit with on-the-ground realities. For example, some rely on old data that have been shown to be incomplete, such as claims that animal agriculture is responsible for over 50% of greenhouse gas emissions when it is actually less than 15%[4] globally, and approximately 4.2% in the U.S[5].

The electricity and transpiration sectors both account for far more GHG emissions in the U.S., almost 60%[6] total. To put this in perspective, if Americans replaced all incandescent bulbs with EnergyStar bulbs, there would be a 1.2% GHG savings. If all Americans went “meatless” for one day a week, there would be just 0.6% GHG savings. Eliminating meat from the American diet would only reduce US GHG emissions by 2.6%[7]. But this might require more cropland to produce enough plant-based protein to replace animal-based proteins. And it might not reduce water use by agriculture more than reduced meat diets[8].

The food that we don’t even eat has big impacts. In 2011, the FAO estimated that approximately one-third of all food produced for human consumption worldwide is lost or wasted. Because over 44% of food waste occurs at home, we might diminish our environmental footprint best by starting with reducing food waste.

Others make the assumption that every acre used for animal agriculture is land that could grow crops. Animal agriculture— even in the U.S.—often occurs on ground unsuitable and/or uneconomical for growing crops. This is typical of western rangelands, where cattle may be the only way by which to produce food on rangeland because there is not enough water to grow crops and cows efficiently to transform grass into protein.

So should you stop eating animal protein like red meat or ignore these warnings? In an era of rapid climate change, we all need to consider how we might reduce our impacts and maintain a nutritious diet. At this same time, health care is the fastest growing expense and about half of all American adults are not eating a nutritious diet[9]. Many of us would benefit by eating a diet that is healthier, one with less red meat and animal fat and more seafood, whole grains, fruits, and vegetables. Changing our diets can reduce our impacts, at least modestly, and improve our health and well-being – also important aspects of sustainability. But to make our world more sustainable, we must go beyond changing our food and agriculture systems.

[1] Burlingame, B. and Dernini, S., 2012. Sustainable Diets and Biodiversity: Directions and Solutions for Policy, Research and Action. International Scientific Symposium, Biodiversity and Sustainable Diets United Against Hunger, FAO Headquarters, Rome, Italy, 3-5 November 2010. In Sustainable Diets and Biodiversity: Directions and Solutions for Policy, Research and Action. International Scientific Symposium, Biodiversity and Sustainable Diets United Against Hunger, FAO Headquarters, Rome, Italy, 3-5 November 2010. Food and Agriculture Organization of the United Nations (FAO).

[1] World Health organization. 2019. https://www.who.int/news-room/fact-sheets/detail/malnutrition.

[2] https://www.scientificamerican.com/article/foods-to-restore-your-intestinal-flora/

[3] EAT-Lancet Commission. 2019. https://www.thelancet.com/commissions/EAT

[4] UN FAO.

[5] US EPA.

[6] US EPA.

[7] White, R. R., & Hall, M. B. 2017. Nutritional and greenhouse gas impacts of removing animals from US agriculture. Proceedings of the National Academy of Sciences of the United States of America, 114(48), E10301–E10308. doi:10.1073/pnas.1707322114

[8] Aleksandrowicz, L., Green, R., Joy, E. J., Smith, P., & Haines, A. 2016. The Impacts of Dietary Change on Greenhouse Gas Emissions, Land Use, Water Use, and Health: A Systematic Review. PloS one, 11(11), e0165797. doi:10.1371/journal.pone.0165797

[9] Centers for Disease Control and Prevention. Chronic Disease Overview. August 26, 2015. Available at http://www.cdc.gov/chronicdisease/overview/.