[Podcast] Plant-based diets and sustainable eating

Rebecca McBride and Lizzie Brown profile photos
Specialist Dietitians, Cromwell Hospital
07 January 2021
Next review due January 2024

If you’re thinking of cutting down on animal products in favour of eating more plants, it’s important to make sure you’re eating a varied diet to get all the nutrients you need. In this episode of the Bupa Healthy Me podcast we’ll explain what a plant-based diet is, how to make sure you’re getting everything your body needs if you’re including more plant-based foods, and answer some of your common questions about sustainable eating. Listen to the podcast below or read on to find out more.

What does eating a ‘plant-based diet’ mean?

Eating a plant-based diet means eating a diet that focusses on wholefoods such as fruits, vegetables, wholegrains, nuts, legumes and seeds. It often limits or excludes animal products such as meat and dairy. The term plant-based is an umbrella term that covers lots of different diets and ways of cutting down on animal products and eating more plants. For example, you might hear terms such as:

Vegetarian. A vegetarian diet is one that doesn’t include meat, chicken or fish. Vegetarians usually don’t include insects, gelatine, animal rennet, stock or fat from animals in their diet either. A vegetarian diet can include fruit and vegetables, grains, pulses, nuts and seeds. It also contains eggs, dairy products and honey.

Vegan. A vegan diet excludes all animal products. This includes meat, chicken, fish, animal rennet, gelatine, stock or fat from animals, as well as dairy, eggs and honey.

But the term plant-based diet doesn’t always mean cutting out animal products completely. It can also mean eating more plant-based foods, while having animal products occasionally. For example:

Pescatarian. A pescatarian diet is one that doesn’t include meat or chicken, but does include fish and seafood.

Flexitarian. The term flexitarian is often used to describe a diet that is vegetarian most of the time, but includes animal products occasionally. For example, choosing meat when eating out at a restaurant.

Why might you choose to eat a more plant-based diet?

There are lots of different reasons you might choose to eat less animal products and more plants. These reasons often vary from person-to-person, and could include:

  • ethical reasons
  • animal welfare concerns
  • environmental and sustainability reasons
  • cultural or religious beliefs
  • health reasons

What are some of the health benefits of eating a plant-based diet?

Some of the health benefits of eating a plant-based diet may include:

  • reducing your saturated fat intake (found in red meat and full-fat dairy products)
  • Increasing your intake of vitamins, minerals and fibre (found in fruit, vegetables, pulses and grains)

In combination with exercise, eating a well-balanced diet that’s low in saturated fat can help you to:

But it’s important to make healthy choices and opt for nutritious foods from a variety of sources if you’re cutting down on animal products. There are also lots of plant-based foods that aren’t healthy. Swapping animal products for alternatives high in fat, salt or sugar won’t provide your body with the nutrients it needs for optimal health.

Can you get all the nutrients your body needs on a plant-based diet?

It is possible to get all the nutrients you need when eating a plant-based diet. But it’s important to ensure your meals are well-planned and varied. There are some nutrients which can be more difficult to get from a plant-based diet, so it’s a good idea to be more mindful of where you get these from. These include:


It’s a common misconception that you can’t get enough protein on a plant-based diet. But if you plan your meals ahead and make healthy choices, you can get enough protein while eating fewer animal products.

Protein is essential for growth and repair of your body. It’s the main component of your muscles, hair, skin and internal organs. It’s also a main component of your immune system and helps to make antibodies that fight disease.

Protein is made up of amino acids. There are 22 amino acids in total. Nine of these are essential, which means you have to get them from the foods you eat. Different foods contain different amounts and combinations of these amino acids.

Many animal foods contain the full range of essential amino acids. But in order to get all the essential amino acids you need from plant sources, you need to combine lots of different sources of plant-based proteins across the day. Good plant-based sources of protein include quinoa, lentils, chickpeas, beans, soy products like tofu and tempeh, nuts and seeds, oats and some plant-based milk alternatives such as soy milk.

Vitamin B12

Vitamin B12 is important to think about when following a plant-based diet, as it’s often the most difficult to get. It’s made by microorganisms and isn’t produced by plants.

Vitamin B12 helps to keep your nerves and blood cells healthy and to make DNA. It also helps to prevent a type of anaemia known as megaloblastic anaemia which can make you feel very tired and weak.

If you’re eating some animal products, then you can get vitamin B12 from milk, cheese, yoghurt and eggs. But if you’re excluding animal products from your diet completely, you’ll need to get vitamin B12 from fortified foods or by taking a supplement. Foods fortified with vitamin B12 can include breakfast cereals and plant-based milks. Nutritional yeast products are also a source of vitamin B12 but check the labels to see how much they contain.


Iron is a mineral that helps to make red blood cells and carry oxygen around your body. It supports muscle metabolism and helps to keeps your connective tissue healthy. It’s also important for growth and neurological development.

Plant-based sources of iron can include fortified breakfast cereals, beans, lentils, chickpeas, spinach and tofu.

But it’s important to note that the type of iron found in plant sources isn’t as easily absorbed by your body as animal sources of iron – like meat. If you eat a good source of vitamin C along with plant-based sources of iron, it helps your body to absorb this type of iron better. Good sources of vitamin C include citrus fruits, kiwi and peppers.

Omega-3 fatty acids

Omega-3 fatty acids are a family of fats that can help to keep your heart and joints healthy. Some studies suggest that they may improve your sleep and memory, and reduce your risk of stroke, but more evidence is needed to confirm this.

Some omega-3 fatty acids can’t be made by your body, so it’s important to get these from the foods you eat. Plant-based sources of these can include vegetable oils such as hemp, rapeseed and flaxseed oils. They’re also found in nuts like walnuts, pecans and hazelnuts, as well as soy products and green leafy vegetables.

Other omega-3 fatty acids can be made by your body, but only in very small amounts. Oily fish is a great source of these omega-3 fatty acids. But, if you’re following a completely plant-based diet you might want to consider taking a plant-based omega-3 supplement to get these.


In combination with exercise, calcium can help to keep your bones healthy. Dairy foods such as milk, cheese and yoghurt are good sources of calcium. But most plant-based milks and yoghurts are now also fortified with calcium, so check the labels to be sure. A small amount of calcium is also found in some dried fruit, nuts, sesame seeds, tahini, tofu, some green leafy vegetables and other fortified foods, such as breakfast cereals.


Iodine is a mineral that’s a key part of the thyroid hormones needed for many body processes, such as growth and metabolism.

Fish and dairy products are good sources of iodine. But the amount of iodine in plant foods depends on the iodine content of the soil where it’s grown, and this can vary significantly. For example, foods grown nearer to the sea can be higher in iodine. So, in regions where soils have less iodine, you can choose foods like seaweed as a source of iodine instead.

It’s important to note that some sea vegetables can be very high in iodine and eating too much iodine may be unhealthy. So, if you’re following a plant-based diet and are concerned about your iodine intake speak to a Dietitian for more advice.


Selenium is important for reproduction, thyroid gland function, DNA production and protecting your body from infection and damage.

Seafood and organ meats are good sources of selenium. But the amount of selenium in plants will depend on the selenium content of the soil it was grown in. Because of this, geographically, the selenium concentration of plant foods can vary a lot.

Good sources of selenium include brazil nuts, brown rice, wholegrain bread, beans, oats and lentils. So be sure to include a variety of these in a plant-based diet.


Zinc helps to support your immune system to fight off harmful germs and heal wounds. It also plays a role in your sense of taste and smell and helps to make the proteins in your DNA.

Meat, poultry and shellfish contain the highest levels of zinc. But it’s also found in plant-based protein sources such as legumes, beans, lentils, nuts and seeds. These plant-based sources of zinc are less easily absorbed by your body, so it’s important to eat a variety of these foods.

What is sustainable eating?

The Food and Agriculture Organisation says that: ‘Sustainable diets are those diets with low environmental impact 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, culturally acceptable, accessible, economically fair and affordable; nutritionally adequate, safe and healthy while optimising natural and human resources.”

So sustainable eating can be described as a way of eating that supports the future of our environment. While it’s important for your diet to be sustainable and protect the environment, it’s also important to make sure your diet gives you all the nutrients your body needs.

If you’d like to try eating a more sustainable diet you could also try:

  • sourcing your food locally and seasonally, for example shopping at your local farmers’ market
  • having one meat-free day a week
  • reducing your food waste, for example freezing or using up leftovers
  • avoiding single-use plastic, such as using a reusable water bottle

What are plant-based milks?

‘Plant milks’ are non-dairy milk alternatives that come from plants instead of animals. For example, soy, almond, cashew, oat, coconut or rice drinks. If you’re choosing a plant-based ‘milk’, check the label to make sure they’re fortified with calcium and vitamin B12 and that they’re unsweetened, without added sugars.

Does importing health foods have a negative impact on the environment?

There’s some debate about the sustainability of certain health foods, such as avocado, quinoa and plant milks. It isn’t always clear the impact that the production and transportation methods used for these has on the environment. Because of this, some people think it would be better for the environment for us to eat locally sourced animal products, rather than imported foods.

When thinking about the environmental impact of these products, it’s really important to consider the whole picture. This might include looking at the greenhouse gas emissions, land, water, pollution, deforestation, soil degradation required to produce them. You could also consider the impact their production has on biodiversity and ecosystems. Each of these factors will be different depending on the country where the food is produced and the farming practices that are used there.

For example, soy products like tofu and soya drinks are significantly more sustainable when compared to dairy products when looking at the greenhouse gas emissions, land and water used to produce them. But for other plant-based milks, the data is more limited. The data we do have indicates that the greenhouse gas emissions are similar to that of soya products, and therefore significantly lower than dairy milk.

On the other hand, the production of rice and nuts can be extremely water intensive, which could mitigate the benefits seen from lower greenhouse emissions for these products.

The amount of water used for growing nuts really varies depending on the country they come from. For example, the amount of water used can range from zero - where only rainwater is used - to 500,000 litres per 100g of protein produced.

Despite this, when you consider the full range of environmental factors involved, nut and other plant-based milks still have a lower environmental impact overall, compared to dairy products.

As well as looking at how these products are produced, it’s also important to consider where they come from and the impact that transporting them around the world has on the environment. For example, transporting food by rail or water is more energy efficient than by air or truck. Some studies show that transportation counts for about 11% of a food’s greenhouse gas emissions.

So, buying food that is produced and grown locally will reduce food miles and the average consumers greenhouse gas emissions. But making lots of small changes such as substituting red meat and dairy for fish or chicken, eggs or vegetables is likely to result in a greater reduction in greenhouse gas emissions than just buying locally alone.

Do soy products contain hormones that are harmful to your health?

Soy is highly acclaimed by some people as a health food because it may reduce the risk of osteoporosis and protect against some hormonal cancers, such as breast and prostate cancer.

But at the same time, soy is shunned by others for fear that it may cause breast cancer, thyroid problems and dementia.

This controversy comes from the fact that soy contains high levels of a type of plant oestrogen that is similar in function to human oestrogen – although it has much weaker effects. These plant hormones have a different action in the body based on a number of factors.

The studies that report that soy is unhealthy are based on lab animals. But because humans digest soy differently to animals, these findings might not apply to humans. Not only this, but many of these studies based on the effect of soy can vary depending on the existing levels of hormones in the body. For example, post-menopausal women have lower levels of oestrogen in their body, so the weak effect of plant oestrogen might help to relieve the symptoms of menopause.

Due to these varying factors, it’s really difficult to make a blanket statement about soy. But from the current studies, there doesn’t appear to be any substantial evidence that soy definitely increases or decreases your risk of health problems.

Putting all the debate to one side, soy does still contain many essential nutrients such as B Vitamins, fibre, magnesium and potassium and it’s also a very good source of protein. Soy protein is also considered a complete protein as it includes all nine essential amino acids.

If you’d like to find out more about sustainable diets, visit the One Blue Dot project from the British Dietetic Association.

Are you interested in learning more about your health? Discover more about our range of health assessments.

Rebecca McBride and Lizzie Brown profile photos
Rebecca McBride and Lizzie Brown
Specialist Dietitians, Cromwell Hospital

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