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Sustainable Diets: What You Need to Know in 12 Charts

We are what we eat, and what we eat has a profound impact on the planet.

When people think about food and sustainability, they typically focus on how the food is produced. Is it, for example, locally sourced, GMO-free, pasture-fed, organic or certified? Just as important, however, is the question of what is eaten.

What we eat is rapidly changing around the globe, as people converge toward diets high in calories, protein and animal-based foods. A new WRI paper, Shifting Diets for a Sustainable Food Future, explores these changes and the challenges they pose for food security and a sustainable future. It shows that just small shifts in the choices consumers make can have a huge impact in reducing agriculture’s resource use and mitigating environmental problems—the average American, for example, could cut their diet’s environmental footprint in half just by eating less meat and dairy. To help shift people to more sustainable diets at a large scale, the paper introduces the Shift Wheel, which harnesses marketing and behavior change strategies already used by the food industry to influence consumer purchasing.

Here’s what you need to know in 12 charts:

We need to close a big food gap.

The world needs to close a 70 percent “food gap” between the crop calories available in 2006 and the expected calorie demand in 2050. This gap stems primarily from population growth and changing diets. Global population is projected to grow to nearly 10 billion by 2050, with two-thirds of people living in urban areas.

Global diets are shifting toward overconsumption.

As nations urbanize and incomes rise, their citizens diversify their diets and consume more calories and more animal-based foods such as beef, dairy, pork, chicken, eggs and fish. Demand for animal-based food is expected to rise by 80 percent between 2006 and 2050, with beef specifically increasing by 95 percent. Some of this growth in demand will support health and welfare gains, but much of it will be driven by overconsumption of food.

All regions already consume more protein than average dietary requirements—with highest consumption in wealthy regions.

Global average per person protein consumption exceeded dietary requirements in all regions in 2009, with each person consuming on average about 68 grams per day— one-third higher than the average daily adult requirement. In wealthy countries, protein consumption was higher still. For example, the average American man eats nearly 100 grams of protein per day, almost double the amount of protein he needs (56 g).

In fact, the gap between the average American’s daily protein needs and amount they’re already getting from plant sources is less than the equivalent of one chicken breast (4 oz, 35 g of protein).

Animal-based foods are generally more resource-intensive and environmentally impactful to produce than plant-based foods.

Beef production requires 20 times more land and emits 20 times more greenhouse gas emissions per unit of edible protein than common plant-based protein sources such as beans, peas and lentils. Chicken and pork are more resource-efficient than beef, but still require three times more land and emit three times more greenhouse gas emissions than beans. When it comes to resource use and environmental impacts, the type of food eaten matters as much, if not more, than how that food is produced.

The biggest beef is with beef.

Beef is extremely inefficient to produce, as cattle consume a huge amount of calories and protein in order to produce a relatively small amount of calories and protein for human consumption (sheep and goat are similarly inefficient converters of feed to food, but are eaten on a much smaller scale globally). As a result, beef production requires large quantities of land and water per unit of protein or calorie consumed.

One-quarter of the earth’s land (excluding Antarctica) is used as pastureland, and beef accounts for one-third of the global water footprint of farm animal production. Beef also has a disproportionate impact on climate change. Ruminants, of which cattle are the most common, accounted for nearly half of all agricultural production-related greenhouse gas emissions in 2010. If cattle were able to form their own nation, they would rank third behind China and the United States among the world’s largest greenhouse gas emitters.

You don’t have to become a vegetarian or vegan to make a difference.

The average American could cut their diet-related environmental impacts by nearly one half just by eating less meat and dairy. Working with the French agricultural research institutions CIRAD and INRA, we modelled the effects of several diet scenarios. When applied to the average American diet in 2009, the ambitious animal protein reduction scenario (which cut people’s meat/dairy/fish/egg consumption in half) reduced per person land use and agricultural greenhouse gas emissions by nearly one-half—or almost as much as the vegetarian scenario (which eliminated meat and fish, but increased dairy consumption relative to the average American). The beef reduction scenarios reduced per person land use and greenhouse gas emissions by 15 percent (replacing one-third of beef consumption with other meats or legumes) to 35 percent (reducing beef consumption by 70 percent, down to the world average level).

Small shifts in diet choices can make a huge impact globally.

When applied globally to populations overconsuming protein or who are high consumers of beef, the ambitious animal protein reduction and beef reduction scenarios could spare between 310 and 640 million hectares (766 million to 1.6 billion acres) of agricultural land, respectively. For the ambitious animal protein reduction scenario, the land spared is roughly two times the size of India. This is more than the entire area of land converted to agricultural use over the past 50 years. The corresponding avoided land use change-related greenhouse gas emissions was 168 billion tons of CO2 equivalent—more than three times total global emissions in 2009! As a result, reducing consumption of animal-based foods among the world’s wealthier populations could free up significant amounts of land—possibly enabling the world to feed 10 billion people by 2050 without agriculture further expanding into forests.

How consumers can shift their own diets.

To make sustainable diet choices easier for consumers, WRI introduces a new protein scorecard ranking foods from lowest (plant-based foods) to highest impact (beef), based on associated greenhouse gas emissions per gram of protein. Encouragingly, some of the lowest-impact foods are also the cheapest to buy.

Shifting billions of people’s diets requires larger, systemic changes.

Efforts to shift diets in the past have largely depended on information and education, including calling for people to become vegetarian or vegan. These efforts haven’t reached scale because they don’t work in step with how people purchase and consume food. Instead, we need to engage leaders in the food sector to experiment with new approaches that increase the share of plant-based protein in consumer choices.

WRI and partners reviewed more than a dozen successful consumption shifts that have already occurred and created a “Shift Wheel.” The Shift Wheel comprises four complementary strategies: minimize disruption, sell a compelling benefit, maximize awareness and evolve social norms. As a next step, WRI will partner with the food service industry to test the Shift Wheel and scale successes.


Always fascinated by the WRI.

While our population doubled to 7 billions, food production trebled. Not exactly a food shortage or gap.

To compound this issue the Developed world wastes 50% of all food leaving the processing or manufacturing plant. So we aren't starving in the Developed world.

Further compounding this issue of food loss is the fact that the Developing and Emerging Nations loose 50% of all food produced before it gets to market because of poor infrastructure whether this is a lack of roads, storage technology or simply a lack of a market.

What we have is a mismatch between where food is produced and where it is needed, further compounded by a lack of funds to purchase the said food.

There is no food shortage. The US certainly needs to reduce its consumption level for it would require 5 earths to support the world if we all lived like the US citizen and 3 earths if we lived as per the EU citizen. These certainly are facts that have to be addressed and consumption levels reduced to a 1 earth sustainable level.

We have ample food to feed close to 13-14 billion people certainly not at the levels currently adopted by the Developed world but more than adequate for the projected peak of 9.4 billion before it declines to around 7 billion again by the end of the 21st century.

For those who pat themselves on the back for being Vegan or vegetarian there are a few sordid facts about food production that should be looked at. Nuts, yes very healthy but consider to produce one Almond nut in California requires 1 litre of water, plus a significant quantity of artificial fertilizer. But we won't speak about the dearth of research results that support the healthy Vegan diet. There isn't any as there are many shortcomings and metabolic inefficiencies when supposed plant equivalent components are metabolised by humans. Unfortunately a Vegan or Vegetarian diet fails to deliver what an omnivore diet does. The big thing is moderation, balance and honesty about what is feasible and what is not.

Whoa! Hold on. We don't make a meal of almonds like people make a meal of animal foods. We should eat at most 1-2 ounces a day. This does not compare to the environmental impact of raising animals to feed people. And why don't we talk about the research supporting healthy vegan diets? There isn't any? Really?? Are you writing from 1910? All long term, peer reviewed published, unbiased research confirms that humans require a diet rich in whole, minimally processed plant foods and little, if any, animal food. Read How Not To Die by Micheal Greger, MD ( and any of Joel Furhman, MD's books ( Then go to the back of their books and follow the references to the real research supporting all their claims. Whole Food Vegan Diets reduce risk of chronic diseases, are gentler on the planet and much kinder to the nonhuman animals we share this planet with.

Suggestion. I would love to see these charts annotated with the fine print, links to the studies that provide these estimates, or the calculations that go into the estimates. I want to know how conservative the estimates are and what assumptions are built into them — and what kinds of geographical or other variations might account for departures in those estimates. I've downloaded the Shifting Diets paper which helps explain some of the assumptions further, but it's hard to see, as an example, how the authors got to that eye-popping stat on beef's emissions due to land-use changes.

Agree! I want to know more about the details and how to calculate.

Hi Kate - thanks for your question. We've answered it here - please see question #7.

Interesting stats on the almonds Anechidna. And food waste is a huge issue that needs to be addressed in respect to feeding the world - probably the major issue. Also many of these articles when it comes to discussing the impact of meat consumption and cattle production only focus on the resources necessary for producing intensively farmed feed lot cattle who consume many of the grains. Large parts of Australia are semi-arid natural grassland and completely unsuited to growing any kind of crop. These areas do support beef cattle with water supplied by natural waterways and underground water. Thus it depends on the type of available agricultural land in each country. Also organic farming often uses livestock alongside crops to support farming practices that avoid artificial fertilisers and weed control. However we do consume too much meat if most of it needs to be produced via intensive feedlot farming. And basically we eat too much. But let's also look at the impact of mono-cropping on resources as well.

Your protein chart shows how well fish perform - wild and aquaculture. But you do not recommend fish. I would love to know the reason.

Why not recommend switching from beef to fish? It's only a bit higher in GHG than legumes and for many people it is a preferable option as it is a kind of meat - as opposed to more vegetables. This is certainly the approach in Asia, where fish is most sought out after meat.

Ok environmental impact is not only GHG emissions... what about all those huge soy plantations destroying forests, or palm oil effects on Indonesian nature? Overfishing the oceans, large amounts of water for rice cultivation? Is not just only reducing animal protein but having smart conscious sustainable practices along food production chains.

Vegetarian or vegan could also have a really negative environmental impact if not managed properly.

In my opinion the main message should be reduce animal protein but whatever diet you decide to have, make wise and conscious decisions as a consumer and/or producer.

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