How much protein do you really need?

From protein powders to bars and high-protein diets, we’re eating more protein than ever. But do we really need to be consuming quite so much? Protein shakes and bars were once the domain of fitness fanatics. But with the rise in the popularity of high-protein diets, like Atkins, the sports nutrition market has exploded – it’s estimated to have nearly doubled in size since 2012.1

Today, many of us see high-protein foods as a simple way to support a healthy, active lifestyle, so we’re sprinkling protein powders into our smoothies, tucking into protein-boosted ready meals and high-protein energy bars.

What is protein?

Protein is a macronutrient, needed by our bodies for a number of essential functions, including the repair and growth of cells and tissues. Indeed, much of the body is made up of proteins, including muscles, bones, ligaments, blood and skin.

Our enzymes, hormones and neurotransmitters are all made of proteins too, so the protein in your diet isn’t just important for tissue repair, but is crucial for fuelling cell communication inside the body.

Twenty different amino acids form the building blocks of protein. Some of these amino acids are created inside the body, while nine can only be found in foods. These last are called ‘essential amino acids’, and include tryptophan and lysine.2 Foods that offer all nine essential amino acids in roughly balanced proportions are called ‘complete proteins’, and include eggs, fish, dairy and a few plant foods, for example quinoa and soya.3

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How much protein do we need?

On average, women should eat 45g of protein a day and men 56g, according to the British Nutrition Foundation.4 This is about two palm-sized servings of pulses, tofu, fish or nuts.5 However, we tend to eat far more than this. In fact, in the UK, most of us consume around 45-55% more protein than we need each day, according to the National Diet and Nutrition Survey.5

How often should we eat protein?

Aim to eat protein two to three times a day.6 But you don’t need to tick off all the essential amino acids at every meal – the body can use amino acids from previous meals to form complete proteins. This means it should be easy to get all the essential amino acids you need, just by eating a wide range of protein-rich food.7

What happens if you don’t get enough protein?

A severe protein deficiency can cause a type of malnutrition called kwashiorkor. It’s more common in developing countries and is very rare in the UK but can occur in the UK, in extreme circumstances such as in people who are coping with severe long-term illnesses or eating a very restricted diets.

Symptoms include:8
  • a swollen stomach
  • muscle wastage
  • stunted growth in children
  • irritability
  • brittle hair
  • more infections than normal
In a 2007 study, published in The British Journal of Nutrition, researchers reported that a shortage of protein in our diets can impair the immune system. This is because amino acids help activate our white blood cells, and are needed to produce infection-busting antibodies.9

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What happens if you eat too much protein?

Experts have pointed to a range of health issues that can be caused by a high-protein diet, such as:

Bone damage

A 2013 review of studies published in ISRN Nutrition found that a high-protein diet can lead to a build-up of acid in the body, triggering calcium to leach from the bones. Researchers found you’re more likely to break your arm when eating a diet rich in protein.10

Kidney stones

The same study also reported a raised risk of kidney stones from a diet that’s high in protein and low in fluids – particularly for diets rich in animal protein, like meat, dairy and fish.11

Extra pounds

Weight gain is another concern. A 2016 study in Clinical Nutrition reported that the extra protein in a low-carb diet was linked to gaining weight in the long-term.12

Make sure you also check the food labels on protein shakes and supplements, as they may contain added fat and sugar – so more calories.

What are the best sources of protein?

If you’re struggling with your appetite, perhaps due to age or illness, a protein shake or bar could help, but experts agree that most of us should be able to get all the protein we need from a balanced diet.

Eat a range of lean proteins, including plant proteins , like tofu, beans, pulses, fish, eggs, seeds, nuts, quinoa, seaweed and soya – and that way you’ll be meeting not just your protein requirements, but getting your fill of vitamins, minerals and healthy fats, too.

Advice is for information only and should not replace medical care. Please check with your GP before trying any remedies.
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Sources

1. Food Manufacture. Sports nutrition: not just about protein. Available from: https://www.foodmanufacture.co.uk/Article/2017/11/23/Sports-nutrition-market-moves-ever-more-mainstream
2. Medical News Today. How much protein does a person need? Available from: https://www.medicalnewstoday.com/articles/196279.php
3. As above
4. British Nutrition Foundation. Protein. Available from: https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/protein.html?start=2
5. BBC iWonder. Should you worry about how much protein you eat? Available from: http://www.bbc.co.uk/guides/z8899j6
6. As above
7. As Source 4
8. NHS Choices. Kwashiorkor. Available from: https://www.nhs.uk/conditions/kwashiorkor/
9. Li P, et al. Amino acids and immune function. Available from: https://www.ncbi.nlm.nih.gov/pubmed/17403271
10. Delimaris I. Adverse Effects Associated with Protein Intake above the Recommended Dietary Allowance for Adults. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4045293/
11. As above
12. Hernandez-Alonso P, et al. High dietary protein intake is associated with an increased body weight and total death risk. Available from: https://www.clinicalnutritionjournal.com/article/S0261-5614(15)00091-6/fulltext

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