Ro Huntriss - Clinical Lead Dietitian & Nutritionist
What is a Plant-Based Diet?
WHAT DOES PLANT-BASED MEAN?
A plant-based diet is a diet that is mainly based on vegetables, fruit, legumes, pulses, grains, nuts and meat-alternatives. This type of diet may or may not include animal products. Vegan, vegetarian, pescatarian and flexitarian diets are all examples of plant-based diets.
WHAT IS A VEGAN DIET?
As the Vegan Society states, veganism in dietary terms denotes the practice of removing all products derived wholly or partly from animals. This includes foods such as meat, eggs, dairy products, poultry fish or seafood, insects, gelatine or animal rennet, stock or fat from animals.
WHAT IS A VEGETARIAN DIET?
The Vegetarian Society states that vegetarians don’t eat products or by-products of slaughter or any foods which have been made using processing aids from slaughter. The lacto-ovo-vegetarian includes dairy products, and eggs. The lacto-vegetarian includes dairy but excludes eggs in addition to meat and fish.
WHAT IS A PESCATARIAN DIET?
A pescatarian diet will include fish but not meat and may or may not include animal produce.
WHAT IS A FLEXITARIAN DIET?
A flexitarian diet is one which still includes animal products but there is an emphasis on plant-based eating, e.g. someone who is plant-based three days of the week.
ENVIRONMENTAL BENEFITS OF A PLANT-BASED DIET
There is substantial scientific evidence that links plant-based diets with environmental sustainability. Animal-based proteins have a greater greenhouse gas (GHG) emission per 100g of protein than plant-based proteins.
For example, beef releases 50kg CO2 per 100g protein but 2kg of CO2 is released during tofu production. In addition, production of plant proteins, with the exclusion of nuts, require a smaller amount of water than animal protein. Similarly, animal production takes up more land than plant production per 100g of protein.
This is due to the fact you have to house the animals and also have land to produce food for the animals. In sheep meat production 185m2 of land is used per 100g protein in comparison to just 7.3m2 for pulses. In recent times, mass deforestation due to animal farming has decreased biodiversity in certain areas which has a knock-on effect on those ecosystems. If more people adopted more of a plant-based approach it would promote biodiversity and help to reduce deforestation due to the reduced requirements of land and other resources.
HEALTH BENEFITS OF A PLANT-BASED DIET
Not only does going more plant-based help the environment but it can bring health benefits too. The increased consumption of plant-based foods tends to lead to a higher intake of fruit, vegetables and fibre, and a lower intake of fat and saturated fat, and the plant-based dietary pattern has been linked to improvements in blood pressure, cholesterol levels and can help to reduce the risk of certain conditions to include type 2 diabetes, heart disease, stroke and cancer.
Additionally, a plant-based diet is typically lower in calories making it easier to manage weight.
4 TIPS FOR FOLLOWING A PLANT-BASED DIET
If you are choosing to go consume a more plant-based diet, there are some considerations that need to be taken into account:
- Most plant protein foods have low-biological value protein which means that many do not contain all the essential amino acids your body needs. Therefore, it is important to eat a variety of plant-based or vegan protein, perhaps through vegan protein powder or vegan smoothies. Eating two low-biological value protein foods together can ensure that all essential amino acids are obtained as well as consuming a variety of plant proteins throughout the day. This is called protein complementation.
- Diets that do not include oily fish are low in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA are omega-3 fatty acids are important for cardiovascular health as well as eye and brain development. Although there is omega-3 found in plants it is found in a different form called alpha-linolenic acid (ALA). Sources of ALA include flaxseed, walnuts, canola oil, and soy. ALA will need to be converted to EPA or DHA in the body. However, the conversion rate is low and will not cause the EPA or DHA levels in the blood to rise significantly. To combat this a supplement derived from algae can be consumed.
- If you are removing meat from your diet you may be reducing the amount of iron in your diet. Plant-based foods such as lentils, chickpeas, beans, tofu hemp seeds, pumpkin seeds and green leafy vegetables contain iron so ensure you include these in your diet. You shouldn’t consume tea or coffee when consuming iron-rich foods as the polyphenols found in tea and coffee can limit the absorption of iron. Whereas, including fruits and vegetables, or cold-pressed juices, with vitamin C will promote the absorption of iron.
- The typical plant-based diet is often low in Vitamin B12. B12 is needed to prevent megaloblastic anaemia and helps to keep nerve cells healthy. Aside from meat and fish, vitamin B12 is found in dairy, eggs and fortified foods such as plant-based milks, breakfast cereals and nutritional yeast. If these foods are eaten in insufficient amounts a vitamin B12 supplement maybe required.
SUPPORT YOUR OWN PLANT-BASED DIET
Overall, choosing to eat more plants will help reduce greenhouse gas emissions and reduce land and water use. If you increase your plant-based dietary choices it may help to manage weight, reduce blood pressure and cholesterol and help to reduce your risk of chronic diseases. However, the diet will need to be nutritionally balanced and supplementation of certain nutrients may be required.
References
1. National Journal of Sport Nutrition and Exercise Metabolism, 1-10