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, 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-rich 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 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 is crucial for fueling 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.

The latter 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 and dairy.³

What does protein do?

Protein is just one of a complicated set of molecules that do all kinds of jobs in your body. In many ways, protein is one of the many building blocks that make you into who you are.

These molecules make up your hair, nails, bones, and muscles. Protein gives tissues and organs their shape and also helps them work the way they should.⁴

What are the different types of protein powder?

Protein powders are condensed sources of protein which commonly come from animal or plant foods, such as dairy, eggs, rice or peas.

Whey proteins are commonly broken down into three common protein powder formulas. Those forms are:⁵

• Protein concentrates

Protein concentrates are produced by extracting protein from whole food using heat and acid or enzymes. Typically, these supply between 60–80% protein, with the remaining 20–40% being made up of fat and carbs.

• Protein isolates

Protein isolate powders contain around 90–95% protein. This is because there is additional filtering process that removes more fat and carbs, which further concentrates the protein.

• Protein hydrolysates 

Hydrolysates are absorbed more quickly by your body and muscles. Protein hydrolysates are produced when acid or enzyme structure is heated further, which breaks the bonds between amino acids.

What protein is used in protein powders?

Whey protein

Whey protein is a mixture of milk proteins and is produced as a by-product of the cheese making process.  

It contains a complete set of amino acids and is especially rich in leucine, isoleucine and valine that are important for muscle growth and maintenance. It is also a good source of calcium, magnesium and phosphorus.

Casein protein

Casein is a high-quality, slow-release protein that contains a lot of Essential Amino Acids (EAAs), which your body can’t produce on its own.

Like whey protein, casein comes from cow’s milk. You can usually naturally find it in milk and cheese products.

Egg protein

Egg-based protein powder is a popular choice as its packed with protein, fat free and contains little to no sugar. Generally, egg-based protein powders are made from the egg white.

It’s a common misconception that the egg white contains all the protein, but there is also lots of protein also contained within egg yolk.

In fact, its around a 50/50 split between egg white and egg yolk. However, the yolk does contain more fat and calories.

Pea protein

Pea protein is a good way getting the protein your body needs whilst being on a plant-based diet.

Not only is it good for protein, it’s also high in fibre and low in sugar, which is ideal to support a balanced diet.

Brown rice protein

Brown rice protein is a popular choice for vegans and vegetarians because it is free from gluten, dairy, soya, wheat and eggs.

How much protein do I need?

Most adults need around 0.75g of protein per kilo of body weight per day. On average, this is 45g for women and 55g for men.⁶

That’s about two portions of meat, fish, nuts or tofu per day. As a guide, a protein portion should fit into the palm of your hand.

How much protein per day?

As above, the recommended protein intake from the UK’s Department of Health states that women should avoid consuming more than 45g of protein per day, while men should not exceed more than 55g.⁷ Have a read of this article on how to get enough protein for more information. 

How often should we eat protein?

You should aim to eat protein two to three times a day.

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.⁸

When should you take protein supplements?

Protein shakes are good to have between meals or as a pre or post-workout snack. You can find out more about this in our When is the best time to have a protein shake article.

What happens if you don’t get enough protein?

Symptoms that indicate low protein can vary drastically due to the vital role it plays in so many aspects of a healthy body.

The most common symptom is oedema, or ankle swelling.

Other symptoms include:⁹

• Bruising
• Muscle loss
• Fatigue
• Cramps
• Brittle or ridged nails

People who experience low protein due to liver problems may also experience fluid collecting in the abdomen. Protein is needed for every function of the body, and low protein can be a sign of other problems such as liver, kidney or heart problems.

In severe cases, protein deficiency can cause a type of malnutrition called kwashiorkor. It’s more common in developing countries and is very rare in the UK.

However, it can occur in extreme circumstances, such as in people who are coping with severe long-term illnesses or eating a very restricted diet.¹⁰

Symptoms include:¹¹

• a swollen stomach
• muscle wastage
• stunted growth in children
• irritability
• brittle hair
• more infections than normal

What happens if you eat too much protein?

Experts have pointed to potential health issues that can be caused by excessive protein intake, such as:

1. Bone loss

A 2013 review of studies published in ISRN Nutrition found that a diet with too much protein can lead to a build-up of acid in the body, triggering calcium to leach from the bones.¹²

2. Kidney stones

The same study also reported a raised risk of kidney stones from a diet that contains excessive amount of protein and low in fluids – particularly for diets rich in animal protein, like meat, dairy and fish.¹³

3. Extra pounds

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.¹⁴

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.

A summary of protein

Even though a higher protein intake can have health benefits for many people, it is not necessary for everyone.

People choosing to use protein powders and other sports supplements should only buy them from a reputable source and should always follow specified guidelines on maximum daily amounts.

They should also be aware that protein sports supplements are not a suitable meal replacement as they do not contain all of the other nutrients and vitamins that a balanced meal should contain.

Evidence for the risks of high-protein diets is inconclusive and more research in this area is needed given the increased use of these supplements.

Last updated: 14 June 2021