What Does Sustainable Nutrition Mean?

We are beginning to hear the phrase ‘sustainable diets’ used everywhere, and as a result individuals are starting to think more and more about the impact of their weekly shop on the planet.

It’s estimated 74% of people are very or fairly concerned about climate change.

This topic of sustainable diets is of course an important one, but the true meaning behind the concept is becoming diluted. People look for black and white answers but the area is not that straightforward.

“Eat this, not this”.

“Buy locally, not from there”.

“Eat vegan”.

“Eat Plant based”.

“Don’t eat seafood. But it’s good for the brain?”

“What about healthy diets?”

Disagreements continue. But is this helpful? Let’s take a look at what the concept of sustainable diets actually is and why it’s so essential that we’re talking about it.

Definitions of a sustainable diet are complex and can cover economic, social and environmental sustainability. What’s important to note is that sustainable diets are not about being 100% vegan or vegetarian 24/7 but are about reducing and limiting intake of animal products and processed foods.

In 2010 the Food and Agricultural Organisation (FAO) stated sustainable diets are: 

“Those diets with low environmental impacts which contribute to food and nutrition security and to healthy life for present and future generations. Sustainable diets are protective and respectful of biodiversity and ecosystems, accessible and culturally acceptable, economically fair and affordable; nutritionally adequate, safe and healthy, while optimizing natural and human resources”.

Wherever food production takes place, the systems are dependent on the environment, whether wild fish caught at sea, sheep grazing on our hillsides or potatoes maturing in the soils beneath our feet. There are three main aspects that are measured when it comes to assessing the sustainability of foods:

  1. Carbon and greenhouse gas emissions
  2. Water use
  3. Land use

Carbon and Greenhouse Gases (GHG)

This topic if often the most discussed area . Carbon emissions are produced during the growing, rearing, farming and transporting of plants, animals and products that we consume. Their storage, cooking and disposal also causes emissions of GHG. The carbon footprint of food is a tricky one to estimate, as it’s so widespread, but is still often used to assess sustainability of a food or product. Fruit and vegetables for example, have a lower carbon footprint than cheese and meat. GHG emissions go further, we should consider how far we are traveling as consumers from home to supermarket, how we are storing food. It all adds up. However this is not the only factor to consider when debating whether a food is sustainable, it’s only one part of the puzzle.

Water use

California’s recent multi-year extreme drought was hard on the state’s agricultural industry. It served to raise awareness about just how much water it takes to produce food, not only in the US but across the globe. Water requirement varies from food to food with some needing significantly more water than others for production. For example, it is estimated 674 gallons of water are required to produce 6 ounces of steak, whereas 52 gallons are required to produce 1 egg and 21 gallons for a salad (The Water Footprint Network). There are many variables at play here, including location. Nuts grown in naturally wet climates may need little to no additional irrigation at all compared to those grown in dry California.

Land use

Where natural land-use such as forests or peat soils are converted for agriculture, the land is converted for the purpose of food. This particularly occurs for soy, oil palm and beef production. When this land is converted, stored carbon is released into the atmosphere. This makes defining the sustainability of food harder to measure. Fertilisers are needed for plant nutrition, but generally have high impacts in manufacture, for example from the soil to where they are applied in the field. However there are farming practices which can be brought in to improve the quality and condition of the land. Some of these involve the animals, while other don’t.

So we’ve established what sustainable nutrition is, but why is all of this important? Sustainable nutrition is key to fixing our current global food system.

2050 is a date which comes up frequently in every debate about food systems: it’s the year when the world population is estimated to reach 9.8 billion people. And the question that always follows is: how are we going to feed all of them? Especially with fewer resources such as land, water and fuel. Let’s look at the statistics.

A significant reduction in GHG emissions are needed, estimated 80%.

All stages of food production impact the environment including:

  • Growing and harvesting
  • Fisheries and livestock
  • Processing and packaging
  • Distribution
  • Retail
  • Cooking and eating

Global food production contributes 15-30% of total GHG emissions in the UK and also accounts for 70% of all human water use.

Not only this, but it is also the leading cause of deforestation, biodiversity loss and soil and water pollution.

As the population grows the impact of food production on the environment increases, putting security of food at risk. Considering the detrimental environmental impact of current food systems and the concerns raised about their sustainability is of upmost importance. Promoting and consuming healthy diets that also have a low environmental impact is crucial for both current and future generations.


  1. FAO 2010 http://www.fao.org/nutrition/education/food-dietary-guidelines/background/sustainable-dietary-guidelines/en/#:~:text=Sustainable%20diets%20are%20those%20diets,for%20present%20and%20future%20generations.
  2. FAO 2019 http://www.fao.org/documents/card/en/c/ca6640en/
  3. BNF https://www.nutrition.org.uk/nutritionscience/sustainability/sustainability.html?limitstart=0
  4. WWF https://www.wwf.org.uk/sites/default/files/2018-03/Food_in_a_warming_world_report.PDF
  5. https://www.watercalculator.org/footprint/foods-big-water-footprint/

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