What is a Sustainable Diet

Did you know one of the best things you can do to help protect the planet is to watch what you put on your plate? Here, guest authors and sustainability experts Hollyn and Daniel break down the hows and whys of a sustainable diet!

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According to the experts at the 2010 United Nations Food and Agriculture Organization and Biodiversity International Symposium, sustainable diets are diets which: 

“[have] low environmental impacts which contribute to food and nutrition security and to healthy lives for present and future generations”. 

In other words, a sustainable diet provides enough nutrients and calories for the global human population.  At the same time, it leaves the planet in a state that allows for future generations to feed themselves in a healthy way. 

Experts from the symposium also said sustainable diets should be: 

  1. protective and respectful of biodiversity and natural ecosystems
  2. culturally acceptable
  3. accessible
  4. economically fair and affordable
  5. nutritionally adequate
  6. safe 
  7. healthy
  8. and allow for optimal use of natural and human resources 

Current trends in agriculture, however, including intensive animal agriculture and monocropping, are bringing us farther away from these sustainable goals. 

Current agricultural practices are:

In fact, food systems contribute up to 29% of global greenhouse gas emissions.  This means that the dietary choices we make can have a big impact on the planet and its climate. 

What can you do, as a consumer of food, to make the global ecosystem more sustainable?

Let’s start with the most impactful changes.

Sustainable Diet Change 1 — Eat Less Meat and Dairy 

Sliced meat at a deli

World Resources Institute experts have confirmed that the number one dietary offender in climate change and poor sustainability is beef.  Beef accounts for almost half of the US agricultural land use and greenhouse gas emissions

Experts from the same study found that animal-based foods overall are responsible for nearly 85% percent of production-related greenhouse gas emissions and nearly 90% of agricultural land use

What Do Greenhouse Gasses Have to Do With Sustainability?

Water vapor (H20), carbon dioxide (CO2), methane (CH4) and nitrous oxide (N20) are a few of the major greenhouse gases (GHG).  They get their name because of their ability to trap heat inside the planet, just like a greenhouse traps heat to help grow plants. 

When radiation from the sun reaches the Earth, some energy is absorbed and some reflected back.  (Typically, this is by ice or snow cover, vegetation, clouds, the ocean, or various gases.) The reflected energy goes back into space, keeping the planet from warming.

But this normally reflected energy can be trapped by greenhouse gases. If this happens, the energy is trapped in the atmosphere and it makes the planet warmer than it should be.  This, in turn, changes weather pattern and harms the health and wellbeing of plants, animals, and ecosystems the world over.

A layer of greenhouse gases – primarily water vapor, and including much smaller amounts
of carbon dioxide, methane and nitrous oxide – acts as a thermal blanket for the Earth, absorbing heat and warming the surface to a life-supporting average of 59 degrees Fahrenheit (15 degrees Celsius).
A simplified animation of the greenhouse effect. Credit: NASA/JPL-Caltech

What Do Meat and Dairy Have to Do with Greenhouse Gases?

The most important and predominant GHGs in animal agriculture are methane and nitrous oxide.  

Methane is mainly produced as a result of fermentation in the gut of a ruminant animal after it eats. The gas is released into the atmosphere either from flatulence or by seeping out of manure.  Methane is 28 times more potent than carbon dioxide as a greenhouse gas. 

Nitrous oxide is also released from manure.  It is 265 times more potent than carbon dioxide as a greenhouse gas. 

These numbers mean that, if you look at animal-based protein based on kg of carbon dioxide equivalent (CO2e) per kg of protein, the numbers are staggering: 

  • beef creates 295 CO2e per kg of protein
  • sheep and goat meat creates 201 CO2e per kg
  • sheep and goat’s milk creates 148 CO2e per kg 
  • cattle milk creates 87 CO2e per kg 
  • pork creates 55 per kg CO2e
  • chicken meat creates 35 CO2e per kg 
  • chicken eggs create 31 CO2e per kg

How Much Does Reducing Meat and Dairy Cut Greenhouse Gases?

Do these carbon emissions mean you have to eat a vegetarian diet to eat sustainably? 

No. 

But the less animal products you consume, the lower your carbon footprint.

Vegan diets have a carbon footprint of up to 102% less than an omnivorous diet (2.94 kg CO2e per day).  Vegetarians rank in at up to 54% less than omnivores (3.85 kg CO2e per day) and pescatarians at up to 51% less (3.94 kg CO2e per day). 

Even just reducing your meat intake can make a big difference.  Omnivore carbon emissions can range from 4.67 kg CO2e per day for low meat-eaters to 7.26 kg CO2e for high meat-eaters. 

And, at least population-wise, it shouldn’t be difficult to reduce animal product intake to make a big difference. 

Animal protein overconsumption is extremely high in the US, Canada, and Europe. In fact, if just half of their populations reduced their average daily consumption of animal protein from 90 g to 60 g, there would be a 40-45% reduction in greenhouse gasses per person.  (Keep in mind that 60 g of animal protein per day is still above the daily recommended intake.)  

Related Reading: The Truth About Meatless Diets

Sustainability Bonus: Reducing Meat and Dairy Reduces World Hunger

Each time you opt for plants over meat, crops are being switched from animal food to human food.  This increases the food supply worldwide.

Indeed, one-third of the global cereal production is used to feed animals.  If we weren’t raising the animals for us to eat, all of that grain could be used to feed people.

Any bit of animal-based protein that you can replace with plant-based protein will be doing the planet and your fellow human begins a favor. 

Reducing or eliminating red meat will have the biggest impact. 

Sustainability Bonus: Reducing Meat and Dairy Intake is Good for Your Health

Cutting out or reducing red meat in your diet not only helps create a healthier planet, but it also reduces your risk of cardiovascular disease and cancerData suggests that a diet that includes mostly whole grains, fruits, vegetables, nuts, and legumes is beneficial to health. 

To give you an idea of what a sustainable diet could look like, a team of experts from around the globe has created a healthy reference diet.  We’ve added it as a table for you here!  

Table breaking down the components of a healthy, sustainable diet
Willet, W., Rockström, J., Loken, B., Springmann, M., Lang, T., Vermeulen, S… Murray, C. J. L. (2019) Healthy reference diet, with possible ranges, for an intake of 2500 kcal/day, p. 451

Tips for a Plant-Based Diet

For those choosing to take the vegetarian or vegan leap, make sure that you are eating foods that provide you with sufficient key nutrients for a vegetarian or vegan diet:

In some cases, supplementation may be necessary to get enough, but most of these nutrients are available in lots of plant-based foods.

And don’t forget, you’re just a Google search away from finding millions of healthy vegan recipes.  

Sustainable Diet Change 2 — Eat Insects 

Person holding street food

Wait,  what? 

Yes, if you want a source of sustainable animal protein, eat insects.

There are thousands of edible insects on the planet.  They are rich in protein, fats, fiber, and micronutrients.  And they have tons of ecological benefits and low environmental impacts

From New York to Portland, stores are starting to sell cricket and other insect powders — and you can even find them in energy bars. (We recommend this brand!)

People eat insects in about 113 countries around the world.  Even the United Nations has recommended eating insects as a food source to help address the global food shortage.  

Read Next: Food is Culture: Sasha de Beausset

Sustainable Diet Change 3 — Consume Fewer Calories 

Orange slice on a blue plate

This only applies if you are exceeding your daily energy requirements.  But that means one in every three U.S. adults

While more than 820 million people in the world remain undernourished, 1-2 billion adults are overweight or obese, meaning they are consuming more calories than they need each day.

By consuming, instead, only what you need and maintaining a healthy weight, you help draw us closer to bridging the food gap — the required increase in food calories to feed 9.7 billion people by 2050.

Plus, eating only what you need helps reduce the amount of agriculture inputs and environmental impacts associated with your diet. Not to mention all of the health benefits that come with a healthy BMI!   

Sustainable Diet Change 4 — Reduce Food Waste

Meal prepped quinoa salads in mason jars

According to the United Nations, roughly 1.3 billion tons of food is lost or wasted globally per year — which is about one-third of total global food production. 

Food can be wasted at many levels along the supply chain — at the post-harvest, processing, retail, or consumer levels. 

In medium and high-income countries, more than 40% of food is lost or wasted.  Often, this is because it is thrown away even though there is nothing wrong with it. 

In low-income countries, more than 40% of the food is lost at the post-harvest or processing levels.

If food waste were a country, it would be the third-largest greenhouse gas emitting country in the world, in large part due to the methane coming from rotting food in landfills.  

Tips to Reduce Food Waste 

Save Leftovers

If you go out to eat, bring Tupperware with you to bring any leftovers home.  This way you don’t consume more than you need, you have an extra snack for later, and you avoid taking home a disposable package from the restaurant. 

Donate Extra Food

Ever go little overboard at the grocery store and end up with enough food to feed a battalion?  Find someone to give the extra food to. There are many apps that help you find people in need of food. 

You can also use those apps to get food from people, restaurants, or grocers that have more than they need. 

Get Good at Meal Planning

Meal planning can also help eliminate food waste!  And there are apps for that too!  Make sure you know what is in the fridge at home and plan to use leftovers.  Buy only what you really need.

Get Creative with Nearly Expired Produce

If fresh food items are past their prime, you can use them to make soups or stir-fries.  And make sure to eat all of the edible parts of foods (e.g. skins, seeds, and stems). 

Create a Home Compost Bin

Finally, you can compost inedible food scraps at home.  This will help by reduce your footprint by eliminating organic waste from making its way to a landfill or other waste facility and producing homemade fertilizer for your plants. 

Sustainable Diet Change 5 — Eat Seasonal, Local Foods 

Local, sustainable vegetables at a farmer's markert

Support local farmers and local markets by buying seasonal food and grow some of your own food if you can. 

When you buy seasonal, local food, or grow your own, you reduce the need for the storage of out-of-season foods.  Plus, you reduce the need for food to be shipped long distances.

Both food storage and shipping can have big carbon footprints, depending on the length of storage, source of energy, and mode and distance of transportation.  Which one’s worse can vary from food to food.

For example, locally grown tomatoes grown out of season during cold temperatures can sometimes have a higher carbon footprint than imported tomatoes because of the energy needed to grow them in a greenhouse. 

And how the food is shipped makes a big difference, too.  Some types of transportation have a much higher carbon footprint than others.  For example, food that is flown by plane has an average carbon footprint of 1,142 kg CO2e.  Food that travels by boat, on the other hand, has an average carbon footprint of just 0.011 kg CO2e

That being said, transportation of food only accounts for about 11% of a food’s GHG emissions. (Production, wherever it takes place, accounts for far more — about 83%). 

This means that choosing low-emission foods (like vegetables and beans) over high-emission foods (like beef) will have a greater impact on your carbon footprint than how far the food traveled by boat. 

Popular on Nutrishatives: The 7 Most Effective Healthy Lifestyle Changes According to Health Experts

Sustainable Diet Change 6 — Eat Whole Foods

Fresh fruit at a market

Why eat whole foods? 

Well, minimal processing of foods leads to higher nutrient availability.  This means you have to eat less food to get all the nutrients you need.

In grains, for example, the milling process strips away many important minerals, vitamins, and fibers.  This leaves you with plenty of calories but insufficient nutrients, meaning you end up having to eat more food. 

If you want to balance out processed foods in your diet, consider adding fermented or sprouted foods.  Fermented and sprouted foods are easy to digest and absorb. You can get lots of nutrients easily from these types of foods.  (Not to mention they are really cheap and simple to make!)  

Sustainable Diet Change 7 — Help Others Change 

If you’ve already adopted the above-mentioned lifestyle changes — or maybe they’ve always been a part of your lifestyle — way to go!  If you’re still looking for ways to make an impact, you have all kinds of options!

  • Spread the word to friends and family about how they can eat more sustainably. 
  • Team up with organizations working to address environmental and climate issues.
  • Get involved in politics to help change food policies. 
  • Volunteer with or found local sustainability projects (like an urban garden or a food sharing group). 

Take Home Message

Our dietary choices have the ability to greatly impact the state of the environment. A sustainable diet should provide sufficient nutrients and calories for the global human population, while still leaving the planet in a state that allows for future generations to feed themselves in a healthy way. 

The most impactful changes we can make to bring us closer to a sustainable diet are: reduce meat and dairy consumption, eat insects, consume fewer calories, reduce waste, and eat seasonal, whole foods.

With this knowledge, the power is in your hands to make the planet a safer and healthier place!  

For additional reading and a complete list of sources referenced for this article, click here.


About the Authors

Daniel is a sustainability master’s student who is passionate about the topics of environmental protection and sustainable development. He has worked in these fields in his hometown, Mexico City, as a part of governmental, international, academic, and non-governmental organizations. In his free time, he likes hiking, playing soccer, listening to music, cooking, and dancing.

Hollyn has always been a nature kid. She grew up playing in the woods around Indianapolis — more often than not adorned with smudges of dirt on her face. Later, she moved down south to Florida, where she completed her bachelor’s degrees in International Studies and Spanish and is currently finishing her master’s degree in Sustainability in Kiel, Germany. She is passionate about environmental and social sustainability and believes that diet is an important way for us all to contribute to a healthier planet. In her free time, she likes going jogging in the woods, dancing dabke, gardening, and spending time with good company.

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