January 2021 Issue

Climate-Friendly Eating
By Sharon Palmer, MSFS, RDN
Today’s Dietitian
Vol. 23, No. 1, P. 22

Dietitians are poised to lead the charge of helping clients transition to more sustainable, healthful diets to improve their health and the health of the planet.

As key leaders in influencing dietary change, dietitians are in the perfect position to promote the importance of a sustainable, climate-friendly diet. According to recent research, diet may be the most significant impact an individual can make over his or her lifetime—even more important than the choice of the car one drives.1 Our work in moving the needle on dietary change among the public is on track with both human health and the health of the planet. Through one-on-one, group, and public health education, dietitians can encourage climate-friendly eating patterns in their practices. And thanks to their special skill sets, RDs also can make these dietary recommendations personalized and actionable. There’s no other profession that enjoys this privilege to help people eat well and sustainably so they can live healthier lives, which in turn contributes to protecting the future.

Hotter Planet
Things have been heating up on the planet in recent years. Although it seems to have been on a low simmer for decades, recent evidence sharply illustrates the plight of climate change. Glaciers are shrinking by miles, drought has led to drops in water levels—Arizona’s Lake Powell was almost at full capacity in 1999 and had dropped to 42% of capacity by 2014—and precipitation may decline by 20% to 25% over most of California, Southern Nevada, and Arizona by the end of the century.2 One of the most destructive results is the increase in wildfires that have been ravishing the country. California’s Camp Fire in 2019 was the state’s deadliest wildfire, taking 85 lives and destroying 14,000 homes. And in 2020, the state coined a new term—gigafire—to describe a blaze that burns at least 1 million acres of land in an already record-setting year of wildfires. The first one was the August Complex Fire in Northern California. The cause is simple—hotter temperatures cause drier land, which creates a parched atmosphere.

The solution isn’t so simple. The most recent period of the Earth’s history has been defined as the Anthropocene, a period during which human activity has been the dominant influence on climate and the environment. Scientists debate whether the Anthropocene began in the 1800s with the Industrial Revolution, when human activity impacted carbon and methane in the atmosphere; 1945, when humans tested and dropped the first atomic bombs, releasing radioactive particles; or 1950 with the Great Acceleration, the dramatic and continuous surge in growth measured by human activity that continues today. Regardless of when it began, the Intergovernmental Panel on Climate Change recommends no more than a 1.5˚ C global warming increase over preindustrial levels. This requires a 70% to 95% reduction in current greenhouse gas emissions (GHGEs) by the year 2050.3

Eating for Health and the Planet
More and more, people are becoming aware of the connection between their diet choices and environmental footprint. In fact, most people think beyond their own health to include the health of the planet. According to the International Food Information Council Foundation’s 2019 Food and Health Survey, 54% of consumers say it’s important that foods they purchase and consume are sustainably produced.4 People are becoming more aware of the need for a sustainable food system, where food is produced using techniques that protect the environment, public health, communities, natural ecosystems, and animals, and results in a reliable food supply for future generations.

The modern food system over the past 50 years vastly has changed the agricultural system and our dietary patterns. The result of these changes, such as larger-scale farms, higher GHGEs, and loss of biodiversity, contributed to the foods that became part of the Western diet, which is rich in highly processed foods, animal foods, and fast foods, and low in healthful, whole plant foods. These foods in the Western diet have made a direct impact on communities and the environment.

The Western diet negatively affects a trio of factors: health, agriculture, and the environment. Traditional diets rely on biodiversity; Western diets rely on a lower variety of foods. According to a study published in the December 2018 Frontiers in Sustainable Food Systems, 75% of the world’s food comes from just 12 plant species and fewer than five animal species, yet we could be consuming from 10,000 plant species, 2,500 animal species, and a greater diversity of fungi and algae.5 Dietitians understand that negative health consequences of consuming highly processed foods, refined sugars, and refined grains over the last 40 years are associated with increased chronic diseases such as diabetes, overweight, and obesity. However, these eating patterns also have impacted planetary health. Overall, today’s agricultural methods increase the use of fossil fuels, GHGEs, and land-use conversion (converting forest ecosystems to agriculture).5 Compared with other dietary patterns, such as the Mediterranean and plant-based diets, the Western diet has a much heavier environmental footprint.

Feeding the world’s 7.8 billion people devastates terrestrial and aquatic ecosystems, drains water resources, and drives climate change, according to research. A study in the December 2018 Frontiers in Sustainable Food Systems reported that the global food supply chain is responsible for 26% of the planet’s GHGEs, 32% of its terrestrial acidification (decline in soil fertility due to acidic nutrients), and 78% of its eutrophication (excessive nutrient richness in bodies of water, often from nutrient runoff resulting in dense plant growth and loss of animal life). The farm stage of food production alone makes up 61% of foods’ GHGEs and uses 43% of the world’s ice- and desert-free land, and more than two-thirds of its freshwater.1 This is even more concerning when considering that the global population is predicted to grow by 2 billion in the next 30 years.

From the farm, food travels by air, water, and land to be manufactured and prepared and packaged before it’s delivered for storage and then distributed to retailers. This is where the consumer enters the food chain, spending energy and using resources purchasing food, transporting it home, cooking and eating it, and ultimately disposing it as waste and recycling. Wasted food products are mostly transported to a landfill, where 30% to 40% of the US food supply is tossed.6

Soil and Sustainability
Another consideration is the health of the soil, which is intertwined in human and planetary health. Soil microbiomes are a complete set of microbes that live in soil ecosystems. These soil microbial communities are essential for sustaining life on the planet, including the cycling of carbon and other nutrients as well as plant growth, and they increase resistance to crop stresses.7

Agriculture threatens soil communities through climate change, soil degradation, and poor land management, which is harmful to the soil microbiome. Agrochemicals, such as inorganic fertilizers and pesticides, lead to severe impacts on soil ecology.8 Healthy soils promote soil carbon sequestration, which removes carbon dioxide from the atmosphere and stores it in a soil carbon pool through plants in the form of soil organic carbon. Unfortunately, the conversion of natural ecosystems to agriculture releases that carbon into the atmosphere. However, reduced tillage, erosion control, organic amendments, and cover crops can increase soil organic carbon.9

Diet Patterns
The foods people choose to eat each day as part of a dietary pattern can make a significant impact on the environment. Research consistently has shown that plant-based dietary patterns—the more plant-based, the better the benefit— are linked with lower environmental impact compared with Western diet patterns. Interestingly, research of nine diets aligned with criteria for a healthful diet specific to 140 countries found shifts in diets to mostly plants and modest amounts of low–food chain animals, such as forage fish, mollusks, and insects, had similar impacts on GHGEs and water footprints as vegan diets. While vegan diets had the greatest benefit, the next best eco-impacts were low–food chain, two-thirds vegan, pescatarian, no dairy, no red meat, vegetarian, reducing meat, and meatless one day a week, which had the smallest degree of benefit.10

Spanish researchers found converting from a Western diet to a Mediterranean eating style also may significantly reduce impact, reducing GHGEs by 72%, land use by 58%, energy consumption by 52%, and water consumption by 33%.11 This lower footprint, research shows, is due to the Mediterranean diet’s decreased levels of meat.12 According to Italian researchers, if an average Italian family consumed a vegetarian diet, it would reduce its annual carbon dioxide emissions by 614 kg per year, the equivalent of the 3,175 km released by an average European car.13

Other sustainable dietary patterns potentially can have environmental and health benefits over the Western diet. Research shows that adopting one of 14 common sustainable dietary patterns (ranging from vegan and vegetarian to Mediterranean and New Nordic) could result in reductions as high as 80% of GHGEs and land use, and 50% of water use. The reductions mostly were proportional to the degree of animal-based food restriction.14

Findings from the Adventist Health Study and California state agricultural data used to calculate dietary consumption patterns compared with environmental effect showed that nonvegetarian diets used 2.9 times more water, 2.5 times more primary energy, 13 times more fertilizer, and 1.4 times more pesticides than vegetarian diets. The greatest contribution to these differences, which also has been noted in many other population studies, was beef consumption.12 The EPIC-Oxford cohort study compared the GHGEs among meat-eaters, fish-eaters, vegetarians, and vegans in the United Kingdom. Dietary GHGEs in kilograms of carbon dioxide equivalent for high meat-eaters was 7.19, twice that of vegans, which was 2.89. The carbon dioxide equivalent for low meat-eaters was 4.67; for fish-eaters, 3.91; and for vegetarians, 3.81.15

Eco-Impact of Livestock
Livestock—from genetics, to food production, to feedlot, to meat processing, to distribution, to plate—is responsible for large amounts of GHGEs, including methane and nitrous oxide, which have greater global warming potential than carbon dioxide. Livestock also contributes to environmental degradation, such as deforestation, land degradation and erosion, loss of biodiversity, increased water use, water pollution, and eutrophication.16 Furthermore, the rise in global intake of animal foods pushes the planetary boundaries to feed people.17

Of the one-quarter of global GHGEs that come from food, more than one-half of those emissions come from animal products—58% from animal products compared with 42% from other foods. One-half of all farmed animal emissions come from beef and lamb.1 The Intergovernmental Panel on Climate Change report uses global average data to estimate that the removal of animal-sourced foods from human diets by 2050 could avoid eight gigatons of GHGEs per year. Limiting consumption of meat or seafood to once a month accomplishes about three-quarters of that goal, suggesting that reducing meat consumption would have huge ecosystem implications.18

Greener Protein Options
Far less energy is needed to produce the same amount of protein from high-protein plant foods, such as soy and pulses, than animal foods.19 Pulses are among the most sustainable plant proteins. They have one of the lowest carbon footprints, are drought tolerant, and enrich the soil through fixing nitrogen, which reduces the need for fertilizers. Pulses also aid food security because one-half of all pulses are grown in developing nations, and because they increase crop diversity, they decrease risk to farmers. Growing pulses can help increase agricultural production to potentially reach the 70% boost in food production we’ll need to feed the world by 2050.

Whole grains are another sustainable protein-containing plant food. According to the Whole Grains Council, eating more grain-based meals could feed more people with less land, compared with the 75% of global agricultural land used for animal products that supply only 17% of food in calories. And rotating crops with whole grains, such as barley, oats, and rye, in the off season can deliver nutrients back to the soil and help protect against soil erosion.20 Whole grains play an integral role in the EAT-Lancet Planetary Health Diet, a global diet developed by the EAT-Lancet Commission that’s healthful for both people and planet. The diet recommends half a plate of vegetables and fruit, and half primarily whole grains, plant proteins, unsaturated plant oils, and modest animal protein.21

Global Meat Reductions
Countries around the world, like the Netherlands, are recommending reducing red meat intake and increasing plant foods.22 China, which dramatically increased meat consumption (its average intake of 13 kg per person per year in 1982 soared to 63 kg in 2016) along with prosperity, has goals in its dietary guidelines to cut meat consumption in half.23 And the British Dietetic Association’s Environmentally Sustainable Diet (One Blue Dot) recommendations for the United Kingdom call for reducing red meat to less than 70 g per person per day, along with avoiding processed meats, and prioritizing high-protein plant foods, such as beans, lentils, soy, nuts, and seeds.24

Targeting Nutritious Foods
Targeting healthful, nutritious foods, such as whole grains, legumes, vegetables, and fruits, is better for human health and the health of the planet. Low-nutrient foods not only require more energy to produce but also provide few nutrients and don’t promote optimal health. The use of resources such as land, water, fossil fuels, and pesticides to produce foods with poor nutritional quality isn’t sustainable. Unfortunately, nearly one-third of calories eaten in the US diet come from this type of junk food.25 And because people haven’t been cooking as much at home over the past several years—before the pandemic, 90% of Americans said they didn’t like to cook—highly processed foods largely are the products people shop for today, so it’s important to recommend whole, nutrient-rich foods.26 Drinking tap water is the most sustainable beverage option, though coffee and tea are good options, too. Soft drinks and fruit juices are the third biggest contributor to GHGEs.27

Stop Food Waste
Between 30% and 40% of the US food supply is wasted, and consumers are directly responsible for upwards of two-thirds of that food waste, which fills one-third of landfills, where it creates GHGEs.6 That’s a large amount of land, water, energy, synthetic inputs, such as fertilizer and pesticides—and carbon emissions—to produce food that’s never consumed. Minimizing food packaging by skipping single-use, disposable straws and cups and eating fast food less often is a sustainable strategy. The average family eats fast food 150 times per year, which creates 1.8 million tons of fast food packaging per year.28

Eat Seasonally and Sustainably
According to the WorldWatch Institute, food typically travels 1,500 to 2,500 miles from farm to plate. A study in Iowa tracked 2,211 miles for one carton of yogurt (milk, sugar, strawberries) to get to the processing plant. In a Swedish study, a typical Swedish breakfast of apple, bread, butter, cheese, coffee, cream, orange juice, and sugar traveled the circumference of the Earth to get to the plate.29 Eating seasonally is better for the environment because it reduces the distance food travels, which means less fuel and fewer GHGEs. Eating with the seasons also supports local agriculture, contributes to food security, and encourages face-to-face interactions in the community. One of the most sustainable things people can do is to grow some of their own food, by planting herbs, edible landscaping, shrubs, and trees. They also can add a composting bin to take it full circle.

Dietitians Are Key Players
It’s vital that dietitians step in to play an active role in promoting sustainable diets. No group of professionals has more hands-on opportunities to nourish and promote this change. According to a British Dietetic Association survey, dietitians are dialed in to what needs to happen. The association emphasizes four key areas in which dietitians can make a difference24:

• improving the availability of sustainable and more healthful foods through policies with government, local authorities, farmers, local producers, and nongovernmental organizations, such as food brands and commercial companies;
• increasing education and knowledge of health professionals and consumers, strongly focusing on under- and postgraduate dietetics training;
• making sustainable diets easier to understand and taking part in conversations to move us toward consensus; and
• ensuring messages are relevant for different population groups, especially teens and different cultures.

— Sharon Palmer, MSFS, RDN, is a plant-based sustainability expert based in Ojai, California.


Top Tips to Promote Plant-Based Eating
Start the day right. Suggest clients add veggies to their breakfast meals.
Join the Meatless Monday bandwagon by eating vegetarian meals on Mondays.
Shop for plants first. Instead of clients planning their menu around meat, recommend they plan it around plants.
Use meat as a seasoning in plant-based dishes instead of making it the main event.
Create a plant-based pantry list. Many plant-based foods such as beans and whole grains are shelf-stable, convenient, and economical.
Get cooking. Encourage clients to plan at least one night per week to try a new vegetarian recipe.
Keep it simple. Not every meal has to involve cookbooks and cutting boards; it can be as easy as black bean burritos, vegetarian chili, or hummus pita sandwiches.
Try international plant-based fare. Many cultures know how to make vegetarian meals right.
Convert favorite dishes. Counsel clients to turn their favorite meat-based recipes into veggie-based dishes for easy lunch and dinner solutions.
Dust off the slow cooker. Advise clients to throw in veggies, herbs, vegetable broth, canned tomatoes, whole grains, and dried beans, and set the cooker on high for four hours or low for eight hours.
Try plant-based dairy products. Provide clients with a list of plant-based alternatives for milk, yogurt, and cheese.
Think “yes.” Tell clients not to dwell on what they can’t have but on what they can have, given the thousands of edible plant species available on the planet.

— SP


1. Poore J, Nemecek T. Reducing food's environmental impacts through producers and consumers. Science. 2018;360(6392):987-992. 

2. Jones J, Miller B. How our planet has changed over time. CNN website. https://www.cnn.com/interactive/2019/09/world/climate-change-before-after/. Published September 2019. Accessed October 14, 2020.

3. Intergovernmental Panel on Climate Change. Global warming of 1.5°C: an IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. https://www.ipcc.ch/site/assets/uploads/sites/2/2019/06/SR15_Full_Report_High_Res.pdf. Published 2019.

4. International Food Information Council Foundation. 2019 Food & Health Survey. https://foodinsight.org/wp-content/uploads/2019/05/IFIC-Foundation-2019-Food-and-Health-Report-FINAL.pdf. Accessed October 14, 2020.

5. Mejía NV, Reyes RP, Martinez Y, Carrasco O, Cerritos R. Implications of the Western Diet for agricultural production, health and climate change [published online December 20, 2018]. Front Sustain Food Syst. doi: 10.3389/fsufs.2018.00088.

6. Why should we care about food waste? USDA website. https://www.usda.gov/foodlossandwaste/why. Accessed October 14, 2020.

7. Jansson JK, Hofmockel KS. The soil microbiome—from metagenomics to metaphenomics. Curr Opin Microbiol. 2018;43:162-168.

8. Kalia A, Gosal SK. Effect of pesticide application on soil microorganisms. Arch Agron Soil Sci. 2011;57(6):569-596.

9. Ontl TA, Schulte LA. Soil carbon storage. Nature Educ Knowl. 2012;3(10):35.

10. Kim BF, Santo RE, Scatterday AP, et al. Country-specific dietary shifts to mitigate climate and water crises. Glob Environ Change. 2020;62:101926.

11. Sáez-Almendros S, Obrador B, Bach-Faig A, Serra-Majem L. Environmental footprints of Mediterranean versus Western dietary patterns: beyond the health benefits of the Mediterranean diet. Environ Health. 2013;12:118.

12. Marlow HJ, Hayes WK, Soret S, Carter RL, Schwab ER, Sabaté J. Diet and the environment: does what you eat matter? Am J Clin Nutr. 2009;89(5):1699S-1703S.

13. Pairotti MB, Cerutti AK, Martini F, Vesce E, Padovan D, Beltramo R. Energy consumption and GHG emission of the Mediterranean diet: a systemic assessment using a hybrid LCA-IO method. J Clean Prod. 2015;103:507-516.

14. Aleksandrowicz L, Green R, Joy EJM, Smith P, Haines A. The impacts of dietary change on greenhouse gas emissions, land use, water use, and health: a systematic review. PLoS One. 2016;11(11):e0165797.

15. Scarborough P, Appleby PN, Mizdrak A, et al. Dietary greenhouse gas emissions of meat-eaters, fish-eaters, vegetarians and vegans in the UK. Clim Change. 2014;125(2):179-192.

16. Food and Agriculture Organization of the United Nations; The Livestock, Environment and Development Initiative. Livestock’s long shadow: environmental issues and options. http://www.fao.org/3/A0701E/a0701e.pdf. Published 2006.

17. Pelletier N, Tyedmers P. Forecasting potential global environmental costs of livestock production 2000–2050. Proc Natl Acad Sci U S A. 2010;107(43):18371-18374.

18. Future Earth. Our future on Earth 2020: science insights into our planet and society. https://drive.google.com/file/d/1chEx2Aewehp1_0nXYnERwUViJI6qR2hi/view. Published 2020. Accessed October 14, 2020.

19. Sabaté J, Soret S. Sustainability of plant-based diets: back to the future. Am J Clin Nutr. 2014;100 Suppl 1:476S-482S.

20. Oldways Whole Grains Council. Whole grains: a sustainable food. https://wholegrainscouncil.org/sites/default/files/atoms/files/WG_SustainableFood_infographic.pdf. Accessed October 14, 2020.

21. Willett W, Rockström J, Loken B, et al. Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. Lancet. 2019;393(10170):447-492.

22. Food-based dietary guidelines–The Netherlands. Food and Agriculture Organization of the United Nations website. http://www.fao.org/nutrition/education/food-dietary-guidelines/regions/countries/Netherlands/en. Published 2015. Accessed October 14, 2020.

23. Milman O, Leavenworth S. China’s plan to cut meat consumption by 50% cheered by climate campaigners. The Guardian. June 20, 2016. https://www.theguardian.com/world/2016/jun/20/chinas-meat-consumption-climate-change. Accessed October 14, 2020.

24. British Dietetic Association. One Blue Dot: eating patterns for health and environmental sustainability: a reference guide for dietitians. https://www.bda.uk.com/uploads/assets/539e2268-7991-4d24-b9ee867c1b2808fc/421de049-2c41-4d85-934f0a2f6362cc4a/one%20blue%20dot%20reference%20guide.pdf. Accessed October 14, 2020.

25. Yang S. Nearly one-third of the calories in the US diet come from junk food, researcher finds. UC Berkeley News website. https://www.berkeley.edu/news/media/releases/2004/06/01_usdiet.shtml. Published June 1, 2004. Accessed October 14, 2020.

26. Martin E. 90% of Americans don't like to cook—and it's costing them thousands each year. CNBC website. https://www.cnbc.com/2017/09/27/how-much-americans-waste-on-dining-out.html. Published September 27, 2017. Accessed October 14, 2020.

27. van de Kamp ME, Seves SM, Temme EHM. Reducing GHG emissions while improving diet quality: exploring the potential of reduced meat, cheese and alcoholic and soft drinks consumption at specific moments during the day. BMC Public Health. 2018;18(1):264.

28. Routley N. Ranked: biggest fast food chains in America. Visual Capitalist website. https://www.visualcapitalist.com/biggest-fast-food-chains-in-america/. Published December 7, 2019. Accessed October 14, 2020.

29. Pirog RS, Van Pelt T, Enshayan K, Cook E; Iowa State University. Food, fuel, and freeways: an Iowa perspective on how far food travels, fuel usage, and greenhouse gas emissions. https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1002&context=leopold_pubspapers. Published June 2001.