A healthy, sustainable diet

Healthy, sustainable diets: what the evidence says

What we eat affects our own health and the health of the planet. This page explains what the science says about healthy, sustainable diets in the UK. It looks beyond carbon and protein. It covers which changes make the biggest difference, which nutrients to watch, and practical ways to eat well for you and the planet.

 

Key points

  • •     Food systems are responsible for around a third of global greenhouse gas emissions. They also use most of the world’s fresh water and are a major cause of biodiversity loss.
  • •     Eating in line with the UK’s Eatwell Guide is linked with better health and a lower environmental footprint, but fewer than one in 100 people meet all of its recommendations.
  • •     A healthy, sustainable diet is rich in plant foods, but it does not have to exclude meat, fish, eggs or dairy. For most people, the evidence supports eating moderate amounts rather than cutting them out.
  • •     What replaces animal foods matters. Wholegrains, beans and lentils, vegetables, nuts, seeds and fortified alternatives help keep a diet nutritionally adequate.
  • •     Iron, iodine and vitamin B12 need particular attention when eating fewer animal foods, especially for teenage girls, women of childbearing age, pregnant women, young children and older adults.
  • •     Eating fewer foods high in fat, salt and sugar and wasting less food are good for both our health and the environment.

 

On this page

•     What is a healthy, sustainable diet?

•     How does what we eat affect the environment?

•     How does the UK diet compare?

•     Why does nutrient density matter for sustainable diets?

•     Do I need to cut out meat and dairy?

•     Which nutrients need attention if I eat fewer animal foods?

•     How can I choose fish more sustainably?

•     Why isn’t it just about individual choice?

•     Frequently asked questions

•     Practical tips

 

What is a healthy, sustainable diet?

A healthy, sustainable diet provides all the nutrients we need for good health throughout life, while having a low impact on the environment. It also needs to be affordable, accessible and culturally acceptable. A diet that is out of reach for many people cannot be considered truly sustainable.

Sustainability is about more than carbon. Food production also affects how much land and water we use, the health of our soils and biodiversity (the variety of plant and animal life). In the same way, a healthy diet is about more than protein. It also needs to provide enough fibre, vitamins and minerals

 

It’s important that the foods we eat support both our health and the health of the planet. But a healthy, sustainable diet does not mean giving up all the foods you enjoy.

 

Small changes, such as eating more wholegrains, beans and lentils and limiting sweet and fatty treats, can all contribute. For people who eat a lot of meat, replacing some of it with plant-based foods is also a positive step.

 

Helena Gibson-Moore, Nutrition Scientist, British Nutrition Foundation

How does what we eat affect the environment?

Food systems include everything involved in producing, processing, transporting, selling, eating and wasting food. Together, they are responsible for around a third of global greenhouse gas emissions. Farming also uses around 70% of the fresh water taken from rivers, lakes and underground sources worldwide, and over a third of the world’s land. It is a major cause of habitat loss.

The environmental impact of different foods varies widely. Globally, animal foods, especially beef and lamb, generally have a much higher footprint than plant foods such as beans, lentils, grains and vegetables. However, local production methods matter. Life cycle assessments (studies that measure a food’s environmental impact from farm to shop) show that UK beef and dairy production has lower emissions than the global average. This is mainly because of rain-fed, grass-based systems that do not rely on clearing tropical forests. But even allowing for differences in the UK, meat and dairy generally still have a higher environmental footprint than plant-based proteins. For most foods, most of the emissions happen on the farm rather than during transport.

One small UK study found that meat was the biggest contributor to the greenhouse gas emissions from people’s diets, accounting for about a third. Drinks, including alcohol, were next, followed by dairy and then cakes, biscuits and confectionery.

Climate change also affects our food. Extreme weather is already reducing crop yields and pushing up food prices. The UK imports much of its fruit and vegetables, so climate impacts in other countries can affect what is available and affordable here.

Food Waste

Reducing food waste is one of the simplest ways to make any diet more sustainable

Food loss and waste is estimated to account for 8% to 10% of global greenhouse gas emissions.

In the UK, households throw away millions of tonnes of food that could have been eaten each year – worth about £1000 a year for a family of four.

How does the UK diet compare?

The UK’s healthy eating model, the Eatwell Guide, is plant-rich. It is based mainly on fruit and vegetables, wholegrain and higher fibre starchy foods, and beans and lentils, with smaller amounts of dairy, eggs, fish and meat. Research using several UK studies found that diets closer to the Eatwell Guide were linked with a lower risk of early death and around 30% lower greenhouse gas emissions. However, fewer than 1% of people meet all of its recommendations.

The latest National Diet and Nutrition Survey shows that 96% of adults do not eat enough fibre, and only 17% of adults meet the 5 A DAY recommendation.

The Planetary Health Diet

In 2025, the EAT-Lancet Commission published an updated Planetary Health Diet. This global reference diet is based on evidence about health, and the Commission then assessed whether it could be produced within environmental limits. It is rich in wholegrains, fruit, vegetables, nuts and legumes, with small to moderate amounts of fish, dairy, poultry, eggs and meat. The Commission estimates that a global shift to this way of eating could prevent around 15 million deaths a year, although this is an estimate based on modelling.

The table compares some of its reference intakes with what adults in the UK currently eat

Food group

Planetary Health Diet reference intake (grams a day)

Average UK adult intake (grams a day)

Wholegrains

210

About 28

Beans, lentils, peas and other legumes

75

About 32

Fish and shellfish

30

About 17

Red meat (beef, pork, lamb) – UK figure also includes processed meat

15

About 52

Sources: Rockström et al. (2025); UK intakes from National Diet and Nutrition Survey and published analyses.

The Planetary Health Diet is a global reference, not UK dietary advice. Some researchers were concerned that the earlier 2019 version might not provide enough of some minerals, such as iron and calcium, for people with higher needs. In the UK, the Eatwell Guide is still the recommended healthy eating model.

Why does nutrient density matter for sustainable diets?

Nutrient density describes how many vitamins, minerals and other nutrients a food provides compared with the calories it contains. In the UK, it is easy to eat enough calories – or too many – while still falling short on nutrients such as fibre.

This matters when we compare the environmental impact of foods. Looking only at emissions per kilogram can be misleading, because foods differ in the nutrition they provide. Researchers are developing ways to combine nutrition and environmental impact in a single score, but this is still a new area of research.

Foods high in fat, salt and sugar, and alcohol

Foods such as cakes, biscuits, confectionery and savoury snacks provide calories but few of the nutrients that are often low in UK diets. They also have an environmental footprint, and so do alcoholic drinks. Having these less often is one of the clearest ways to improve both the healthiness and the sustainability of our diets.

Do I need to cut out meat and dairy?

No, the evidence supports a diet rich in plant foods with moderate amounts of animal foods. Meat, fish, eggs and dairy provide good-quality protein and important nutrients, including iron, zinc, iodine, calcium and vitamin B12.

UK health advice is that people who eat more than 90g of red and processed meat a day should cut down to 70g or less. More than a quarter of men aged 19 to 64 eat more than 90g a day. It’s estimated that cutting down to 70g would help reduce emissions, with little effect on the number of adults with low iron intakes.

Some climate advisers recommend bigger reductions. For example, the UK Climate Change Committee, which advises the government on climate targets, recommends that average meat consumption falls by 25% by 2040 and dairy consumption by 20% by 2035.

What replaces animal foods matters. Dietary modelling by Food Standards Scotland found that replacing some meat and dairy with foods such as wholegrains, vegetables, beans, lentils, fish, eggs and fortified alternatives can keep diets nutritionally adequate and lower emissions. People would not need to change how they eat completely.

Vegetarian and vegan diets are linked with lower greenhouse gas emissions and land use. They are also linked with a lower risk of some diseases, such as heart disease and type 2 diabetes. However, this evidence is mainly observational, and people who follow these diets may be healthier in other ways too. A well-planned vegetarian or vegan diet can provide most of the nutrients we need, but some need particular attention. Read our page on vegetarian and vegan diets for more information. [add link]

 

 

“It is important that eating fewer animal foods does not make low nutrient intakes worse, particularly for teenage girls, women of childbearing age, pregnant women, young children and older adults.”

 

Angie Jefferson, Registered Dietitian, British Nutrition Foundation

Which nutrients need attention if I eat fewer animal foods?

Animal foods are major sources of several nutrients in UK diets. Some groups already have low intakes, so it is important that eating fewer animal foods does not make this worse.

For example, a 12-week clinical trial encouraged people to follow a mainly plant-based diet with less meat and dairy. The researchers found that this improved some aspects of diet quality and reduced food-related emissions by about a third. But this shift also led to significant reductions in key micronutrients, increasing the risk of inadequate intakes of vitamins B6, B12 and riboflavin, calcium and zinc.

Including plant sources of these nutrients, and in some cases supplements, can help make sure that diets with few or no animal foods provide everything needed for health.

Iron

Iron is needed to make red blood cells. Almost half of teenage girls and a third of women in the UK have iron intakes below the recommended level. The iron in meat is absorbed much better than the iron in plant foods. Substances such as phytates (in wholegrains and beans) and polyphenols (in tea and coffee) can reduce how much iron we absorb from plant foods. Eating foods rich in vitamin C, such as fruit and vegetables, at the same meal can help absorption.

Iodine

Iodine is needed to make thyroid hormones, and is particularly important in pregnancy for the baby’s brain development. In the UK, the main sources are milk and dairy foods, fish and eggs. On average, women of childbearing age have iodine levels slightly below what is considered adequate. Most plant-based alternatives to milk do not contain added iodine. Seaweed is not a reliable source, as it can contain very high and variable amounts. If you do not eat animal foods, choose foods fortified with iodine or consider a supplement.

Vitamin B12

Vitamin B12 is needed for healthy blood and nerves. It is found naturally only in animal foods, so people following a vegan diet need fortified foods or a supplement. Fortified foods include some breakfast cereals, plant-based drinks and yeast extract. Deficiency is uncommon in the general population.

Choosing plant-based drinks

A 2025 report by UK government advisers found that soya, almond and oat drinks are not nutritionally the same as cows’ milk. They can contain less saturated fat and more fibre, but may also contain more sugar and less iodine and vitamin A. This matters most for young children, who get a large share of their nutrients from milk.

  • Choose unsweetened versions.
  • Check the label for added calcium, iodine and vitamin B12.
  • Be aware that organic plant-based drinks are not allowed to be fortified with vitamins and minerals.
  • For children under five, follow NHS advice before replacing cows’ milk.

Protein for older adults

Most people in the UK eat more than enough protein, but a third of adults aged 75 and over eat less than the amount recommended. Animal proteins are generally easier to digest and better at helping to maintain muscle. For older adults, a mix of animal and plant proteins is a practical approach.

How can I choose fish more sustainably?

UK advice is to eat at least two portions of fish a week, one of which should be oily, such as salmon, sardines or mackerel. Most adults in the UK eat about half this amount. Globally, more than a third of fish stocks are overfished. To help:

  • Choose a wider variety of fish and seafood, such as mussels, mackerel and hake, rather than mainly cod, haddock, tuna, salmon and prawns.
  • Look for independent certification schemes for wild-caught and farmed fish.

Why isn’t it just about individual choice?

Healthier, more sustainable choices are not equally easy for everyone. In the UK, families with children in the poorest fifth of the population would need to spend about 85% of their disposable income to follow the Eatwell Guide.

What people can eat also depends on the foods available locally, the cost of transport, and whether a household can afford the energy to cook and has space to store and prepare food. Supporting healthier, more sustainable diets for everyone needs action across the food system, alongside individual changes.

What changes can I make to eat a more sustainable diet?

The balance of foods that we consume is not only important for our own health, but also the health of our planet.

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Eat a more 'plant-rich' diet

Research shows that eating a diet that is plant-rich can have benefits for our health and reduce the environmental impact of what we eat.

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Make sure to get at least 5 A DAY

Fruit and vegetables tend to have a lower environmental impact, in terms of greenhouse gases and land use, than some other types of food.

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Choose sustainably sourced fish

Demand for fish has more than doubled in the last 50 years. This huge increase has meant that about a third of global fish stocks are now considered overfished.

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Choose more plant-based sources of protein

We should aim to include more plant-based sources of protein in our diet. You can do this by eating more beans and other pulses, nuts, seeds, and plant-based meat alternatives.

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Limit foods high in fat, salt, and sugar

We all know foods such as cakes, biscuits, pies, and pastries are not healthy choices, but they can also contribute to the greenhouse gas emissions associated with our diets.

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Try to reduce your food waste

Reducing the amount of food that we waste is a key part of making our diets more sustainable, whatever type of diet we choose to eat.

Practical tips

Eat more plant foods

•     Go half and half. Replace some of the mince in dishes such as Bolognese, chilli or lasagne with lentils or beans. 

•     Eat beans, lentils and chickpeas more often. Canned pulses are affordable and convenient, and provide protein, fibre and iron.

•     Try other plant proteins such as tofu, soya mince, textured vegetable protein or mycoprotein in dishes like stir fries or Bolognese.

•     Snack on a handful of unsalted nuts or seeds.

•     Aim for at least 5 A DAY. Add extra vegetables to curries, soups and stews. Frozen and canned fruit and vegetables count and can help reduce waste.

•     Choose wholegrain and higher fibre versions of bread, pasta, rice and breakfast cereals.

•     Mix your protein sources. Include beans, lentils, nuts, seeds, eggs, fish, dairy and smaller amounts of meat.

•     Check plant-based alternatives. Choose unsweetened drinks fortified with calcium, iodine and vitamin B12, and meat alternatives lower in salt.

Have foods high in fat, salt and sugar, and alcohol, less often

•     Be portion wise. Put a small amount of crisps or chocolate in a bowl rather than eating from the pack. Read our page on portion sizes. [add link]

•     Out of sight, out of mind. Keep less healthy snacks out of easy reach, and put a bowl of fruit where you will see it.

•     Plan ahead. Add healthier snacks to your shopping list, such as fruit, yoghurt or wholegrain toast with peanut butter.

Waste less food

•     Plan your meals, keep your fridge at 0 to 5°C, use your freezer and know the difference between ‘use by’ and ‘best before’ dates.

Cut down the amount of food you throw away

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Set your fridge to the correct temperature

The average fridge temperature in the UK is set at 7°C, which is higher than the recommended range of 0-5°C.

Love Food, Hate Waste

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Know your date labels

Knowing the difference between ‘best before’ and ‘use by’ dates can help to prevent you wasting food

Food Standards Agency

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Store food correctly

Check food labels when you get your shopping home to help ensure food stays fresh for as long as possible

Food Standards Scotland

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Use your freezer

UK households waste 20 million slices of bread every day, but much of this waste could be prevented.

Love Food, Hate Waste

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Plan your meals

Choose foods with the longest ‘use by’ date if you are not sure when you will use them

Planning

Sustainable diet FAQs

The term plant-based diet can be used in different ways – sometimes to mean excluding some or all animal foods as in vegetarian or vegan diets, and sometimes to mean a diet made up mainly of plant foods.

At the British Nutrition Foundation, we prefer the term ‘plant-rich’, which means a diet high in plant foods like vegetables, fruits, lentils, beans and other pulses, nuts, seeds, and wholegrain foods, but that doesn’t exclude animal foods.  The Eatwell Guide is plant-rich, but it also includes some dairy, eggs, fish and meat.

Vegan diets are linked with lower greenhouse gas emissions and land use, and a well-planned vegan diet can be healthy. But you do not need to be vegan to eat more sustainably, and vegan diets need careful planning to provide enough iodine, vitamin B12, calcium and iron.

 

See ‘Do I need to cut out meat and dairy?’ and ‘Which nutrients need attention if I eat fewer animal foods?’ above.

Not always. Although estimates vary, on average, transport makes up only around 6% of the carbon footprint of food, because most food is transported by sea. What we eat usually matters more than where it comes from: local beef still has a much higher footprint than imported beans or lentils.

 

The main exception is food that is flown in, which has a much higher transport footprint. Choosing local and seasonal produce can help, but changing the balance of what we eat makes a bigger difference.

Plant-based alternatives to meat, such as burgers and sausages, generally have a lower carbon footprint than the meat products they replace. On average, they are lower in calories and saturated fat and higher in fibre.

 

However, they vary widely. Some are high in salt and provide less protein, iron and vitamin B12 than meat. Check the traffic light label on the front of the pack and choose products with more greens and ambers and fewer reds.

Most plant-based alternatives are classed as ultra-processed because of the way they are produced and the ingredients they contain. Studies link diets high in ultra-processed foods with poor health outcomes, but questions remain about exactly what causes health effects.

 

Subgroup analysis studies, which means researchers break down the massive 'UPF' category to look at specific types of food, have found that plant-based options like meat and dairy alternatives are less strongly linked to poor health than ultra-processed animal products or sugary drinks.

 

For now, the nutritional content of a product is a better guide than whether it is processed. Read our page on ultra-processed foods for more information.

Related pages

 

Key references

Tips to increase your fruit and vegetable intake

Try having fruits like an apple, banana, or satsuma as a snack.

Add extra fresh, canned, or frozen vegetables when cooking your favourite recipes, such as curries, soups, or stews.

Sprinkle a handful of dried fruit or chopped bananas on your breakfast cereal in the morning.

Choose sustainably sourced fish

Fish is a good source of protein, vitamins and minerals, and oily fish such as salmon, sardines and mackerel also contain omega-3 fats that are thought to be beneficial for heart health. Government advice in the UK is that we should eat at least two portions (140g each) of fish per week, one of which should be an oily fish.

Although the amount of fish we typically eat in the UK is about half this amount, demand for fish globally has more than doubled in the last 50 years. This huge increase in demand has meant that about a third of global fish stocks are now considered overfished. It is important that we ensure a more sustainable future for fish and other seafood by making more environmentally responsible choices when shopping. 

Here are a few tips:

  • Choose a wider variety of fish: There are a wide variety of seafood species available to buy in the UK, but we tend to buy only a small number, known as 'the big 5' (cod, haddock, tuna, salmon, and prawns). Try experimenting with other seafood species, for which stocks are thought to be more abundant, or those that are caught or farmed more responsibly, such as mussels, mackerel, and European hake.
  • Look out for ecolabels on certified fish products: The blue Marine Stewardship Council (MSC) logo; the Soil Association (Organic) logo; Aquaculture Stewardship Council (ASC) certification; and RSPCA monitored logos (see below). These are certifications that provide assurance fish and seafood has come from more sustainable sources that set standards for managing stock levels and animal welfare.

Choose more plant-based sources of protein 

Meat is a good source of protein and provides essential vitamins and minerals, such as iron, zinc, and vitamin B12. It is not necessary to cut out meat from our diet completely to be more sustainable. 

However, we should aim to include more plant-based sources of protein in our diet. You can do this by eating more beans and other pulses, nuts, seeds, and plant-based meat alternatives (such as soya or tofu) that are not high in saturated fat or salt.

Tips to increase plant-based protein foods in your diet

Add a can of beans or chickpeas to replace some (or all) of the meat when cooking dishes such as chilli or curry. Canned pulses are an affordable and convenient protein source and provide fibre and other essential nutrients.

Try a handful of unsalted nuts or seeds as a healthier snack.

Use plant-based protein such as tofu, soya mince or textured vegetable protein (TVP) or mycoprotein to make some of your favourite dishes, like stir fries or bolognese.

Limit foods high in fat, salt, and sugar

We all know foods such as cakes, biscuits, pies, and pastries are not healthy choices, but they can also contribute to the greenhouse gas emissions associated with our diets, as well as land and water use. Limiting these foods in our diet can be a good way to reduce our environmental footprint, especially if we eat these foods often or in large amounts. 

Tips to reduce foods high in fat, salt, and sugar in your diet

Be portion wise: If you occasionally enjoy snacks high in fat, salt, or sugar, try to portion them out to avoid eating lots of calories in one go. For example, put a handful of crisps or nuts in a bowl and leave the rest for later. For more information on healthy portion sizes read our 'Portion Sizes' page.

Out of sight, out of mind: Avoid having snacks high in fat, salt, or sugar easily at hand around the home, as this might mean you are more tempted by them. Try replacing these with healthier alternatives, for example by putting a bowl of fruit on the kitchen table or next to your computer at home or at work.

Plan: Make a list of healthier snacks to buy before you go shopping. If you tend to have a mid-morning or mid-afternoon snack to fill a gap between meals, plan out healthier options you can have, such as a slice of wholegrain toast and peanut butter. Read our page on healthier snacking.

Waste less food

Reducing the amount of food that we waste is a key part of making our diets more sustainable, whatever type of diet we choose to eat. It’s been estimated that food losses and waste contribute as much as 10% of greenhouse gases emissions. If food waste were a country, it would be the third largest emitter of greenhouse gases (behind China and the US). However, less than a third of us in the UK make a clear link between wasting food and climate change, even though 8 out of 10 of us are concerned about climate change as an issue. 

In the UK, we have reduced the amount of food we waste in recent years by 7% (between 2015 and 2018). While it may not sound like a lot, that is enough food waste to fill the Royal Albert Hall ten times! It is also estimated this has saved the UK public over £1 billion per year.

Last reviewed November 2026

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