Protein: What is it and how much of it do we need?
Article by Abbey Griffiths ANutr
Protein is vital for building and repairing tissues and supporting overall health. It comes from both animal and plant-based sources, with animal proteins typically containing all essential amino acids. To ensure complete protein intake on a plant-based diet, combine different sources like beans and rice.
A balanced diet usually meets protein needs, which are about 0.75 grams per kilogram of body weight for most adults, but higher for athletes and older individuals. While supplements can be helpful for elite athletes, most people can get enough protein from whole foods. Prioritising diverse, nutrient-rich options can help support both your health and the environment.
Have you heard of macronutrients?
As one of three macronutrients, in addition to carbohydrates (carbs) and fat, protein is essential for building and repairing body tissues and the production of enzymes and hormones.
During digestion, our bodies break proteins down into their constituent amino acids (of which there are 20) and these are then used to build new proteins.
Although our bodies have the ability to produce some amino acids, known as non-essential amino acids, there are nine amino acids that we cannot self-produce and must obtain from our diets.
A complete protein is one which contains all nine essential amino acids. While animal proteins tend to be complete, this is the case for only a few plant sources, including tofu, quinoa and buckwheat. However, by pairing different plant-based protein sources, we can ensure we consume all of the essential amino acids. Example combinations include beans and rice and peanut butter with wholemeal bread.
Plant vs animal?
Because not all plant-sources of protein are complete proteins, it is important for anyone with a plant-based, vegetarian or vegan diet to consume a variety of plants to ensure their diet includes all of the essential amino acids. Plant diversity is not only important for protein intake but for gut health, as well. It is suggested, therefore, that we should aim to consume 30 different plants each week.
Despite many plant proteins being incomplete, they are still great sources of protein. On the whole, in the UK, we want to increase our intake of plant-protein. A diet that incorporates more plants can help to reduce our environmental foot-print and benefit our health. For example, plant-based sources of protein are packed full of fibre, which is beneficial for our health. In the UK, on average, we do not meet the 30g daily fibre recommendation, so switching to plant-based protein sources is a great way to help us reach this. Plant-based protein sources are also often cheaper!
There is room for both animal and plant-based sources of protein within a varied diet, but given the low intake of plant-based protein sources in the UK, we should try to prioritise these where we can. Simple tweaks to meals can increase our plant protein intake, such as adding less beef mince to a Spaghetti Bolognese, and substituting it for lentils, or adding a tin of chickpeas to a curry.
Animal-based protein sources include:
Meat
Fish (aim for two portions of fish each week, including one oily fish)
Dairy (such as milk, cheese (cottage cheese is a good option) and yoghurt)
Eggs
Plant-based sources include:
Pulses (such as beans, peas and lentils)
Nuts and seeds
Other plant-based protein sources, such as tofu, tempeh and mycoprotein
How much protein do you need each day?
In the UK, protein requirements are calculated on the basis of body weight. For adults, the recommendation is 0.75 grams of protein per kg of bodyweight. Based on UK averages, the daily recommendations equate to 56g/day for men and 45g/day for women.
However, it is important to note that our requirements can vary according to factors such as age and activity levels, with some groups in the population requiring more protein than others. Those who exercise regularly, such as elite athletes, are advised to consume 1.2-2g of protein per kg of bodyweight per day, while older individuals have higher protein requirements than other adults to help manage sarcopenia, the progressive loss of muscle mass associated with ageing.
Supplements
Protein powders and bars have become very popular in recent years, but do we actually need them?
Unless you are an elite athlete or have a very specific performance goal, the answer is probably no. In the UK, on average, we exceed the recommended amount of protein and do not require protein supplements.
For the regular gym-goer or recreational sportsman, there is no need to take protein supplements. Although the recommendations are slightly higher for active individuals, these levels should be attainable with a balanced diet, without the need for supplements.
For elite athletes or individuals with specific performance goals, it may be beneficial to take protein supplements because they are convenient and transportable. Athletes, in particular, may find them a useful means of consuming protein when they do not feel hungry after an intense workout. Supplements should only be used, however, to complement a healthy balanced diet and to supplement your normal intake. We should focus on sourcing protein from nutrient-dense whole foods that allow us to meet a wide range of ‘other’ nutritional needs.
It is also prudent to exercise caution when selecting supplement products. Protein powders and bars often contain many additional ingredients, such as sweeteners, meaning they qualify as an ultra-processed food, many of which are detrimental to gut health. If you choose to use protein supplements, compare brands and choose products that contain the fewest ingredients. Always be mindful of ingredients you would not find in your cupboard at home!
Summary
Protein is one of three macronutrients and an essential part of our diet. Protein comes from both animal and plant-based sources. Although animal sources of protein tend to provide all of the amino acids we need, plant-based proteins are still an excellent source to include in our diet. This is true in terms of the benefit to our health and the environment. The recommended protein intake in the UK is 0.75 g/kg of body weight. Remember, however, that this does not account for people of different ages or activity levels. For highly active people, protein requirements can be as high as 2g/per kg of bodyweight. When it comes to protein intake, prioritise sourcing as much as possible from wholefoods that will allow you to reach all of your nutrition targets. Supplements should complement a healthy, varied diet and must not be relied upon too much.
About the author
This blog post was written by Abbey Griffiths. Abbey is a Registered Associate Nutritionist (Anutr) who has degrees in both Sport and Exercise Science and Human Nutrition. Abbey is passionate about the power of nutrition and exercise to optimise health and wellbeing. You can find her on Instagram @abbeyg_nutrition.