Protein has moved well beyond the world of bodybuilders and dedicated gym-goers.
It is now being added to an ever-growing range of everyday foods and drinks, from breakfast cereals, bagels and chocolate bars to coffee.
Starbucks has added protein-enriched beverages to its UK menu, while Costa has been testing lattes containing 23g of protein — about the same amount found in a small chicken breast.
This month, Caffè Nero also teamed up with sports nutrition company Myprotein to launch iced lattes containing up to 25g of protein, offering a sizeable serving of the muscle-supporting nutrient with a caffeine boost.
Protein is one of the three primary nutrients, alongside carbohydrates and fats. It is needed to build and repair muscle, keep skin supple and hair strong, and produce essential hormones.
But can a daily chicken breast or a couple of eggs provide all the protein we need? And is a liquid protein supplement worth the money? Registered nutritionist Emma Bardwell explains what to consider.
Protein is essential for building and maintaining muscle. That includes skeletal muscle, the muscles that help the heart beat and those that open the airways for breathing
How much protein should I eat per day?
The NHS advises adults to consume 0.75g of protein per kilogram of body weight each day. For someone weighing 70kg, that is approximately 52.5g — the equivalent of two medium chicken breasts or two scoops of protein powder.
However, Bardwell says healthy, active adults in midlife and later years may wish to aim for around 1.2–1.6g per kilogram of body weight daily, depending on their activity levels and individual circumstances.
As we age, the body becomes less efficient at using dietary protein to build and preserve muscle. Increasing protein intake can therefore help support strength and mobility.
For some people, that could mean consuming 84–112g of protein a day — roughly the amount found in three and a half tins of tuna or a large pot of Greek yoghurt.
There is a potential downside, however: consuming excessive amounts of protein may place additional strain on the kidneys.
Experts say this concern applies mainly to people who already have kidney disease. Those patients are generally advised to restrict protein intake to about 0.55-0.8g/kg per day — approximately 52g for the average woman and 64g for the average man.
More recently, experts have also warned that otherwise healthy young people may be developing kidney stones as a result of extremely high-protein diets.
Kidney stones are small, hard deposits made from salts and minerals, including calcium. They can cause no symptoms until they travel into the ureter — the tube that carries urine from the kidney to the bladder — where they can trigger excruciating pain. If a stone becomes lodged, the condition can be life-threatening.
“Eating a lot of protein makes urine acidic, increasing the amount of uric acid while also raising calcium levels, partly because the acidity causes calcium to be released from bone. It also reduces citrate, a natural inhibitor of stone formation. As a result, stones can develop more easily,” said Vimoshan Arumuham, a consultant urological surgeon at University College London Hospital.
Protein shakes versus everyday foods – which is healthier?
A standard protein shake typically contains around 20–25g of protein, compared with approximately 32g in 100g of cooked chicken breast.
Two large eggs provide about 12–13g, so you would need to eat four to consume roughly the same amount as a protein shake — which can be prepared in seconds, rather than waiting for a pan of water to boil.
Starbucks, Costa and Cafe Nero have launched drinks containing added protein
“Your body can digest and absorb protein from shakes and solid foods equally,” Bardwell explains.
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Gram for gram, protein powders can actually work out cheaper than ordinary foods. Four large free-range eggs from Tesco will set you back £1.40 and provide around 31g of protein.
Getting the same amount from Sainsbury’s own-brand protein powder costs approximately £1.12 – a saving of 28p.
However, the eggs also provide other nutrients, including choline and vitamin B12, which the powder may not contain.
What fills you up more, shakes or whole foods?
‘Solid foods tend to be more filling than liquids, partly because chewing and time spent eating help feelings of fullness,’ Bardwell explains.
‘A protein shake might contain 25g of protein, but it doesn’t necessarily keep you as satisfied as a meal containing the same amount, particularly if that meal also has fibre and healthy fats.’
‘Whey protein is digested relatively quickly, whereas protein from whole foods tends to be digested more slowly because it’s part of a more complex food.’
A protein shake can contain hundreds of calories, yet may not keep you as full as a frittata with beans – something worth considering if you’re trying to lose weight.
Experts say this could leave you vulnerable to snacking behaviour, increasing the total calories you consume in a day, which carries a risk of weight gain.
One of the strongest arguments for eating protein-rich foods instead of relying on shakes, bars and powders is that they provide considerably more nutrition than protein alone.
Greek yoghurt supplies calcium and vitamin B12, eggs contain choline, and oily fish such as salmon provide beneficial omega-3 fats.
These ‘natural added extras’ are particularly relevant when it comes to fibre, which supports digestive health and is associated with a lower risk of several chronic diseases, including bowel cancer.
Most UK adults consume substantially less than the NHS’ recommended 30g of fibre daily. There’s a risk that replacing meals with protein shakes could further reduce opportunities to up your fibre content.
Whey, casein, soy and pea – which protein is best?
Anyone who has ventured into the supplement aisle will have encountered a bewildering selection of products promising everything from faster recovery to healthier skin and hair.
Among the most popular is whey, a milk-derived protein containing all nine essential amino acids.
Many sports nutritionists consider it the gold standard due to its high quantity of leucine – the amino acid that triggers muscle protein synthesis.
Casein, another milk protein, is digested more slowly but can also support muscle maintenance and growth, particularly if taken at night, before bed.
Then there are whey isolates, which undergo additional filtration to remove more fat and lactose, and hydrolysed proteins, which have been partially broken down to speed up digestion.
‘Unless you have a particular medical or digestive need, there’s little convincing evidence that this translates into better results for the average person,’ says Bardwell of hydrolysed protein.
Soy contains all nine essential amino acids, while pea protein is lower in some of them. But eating a variety of plant proteins throughout the day can make up the difference.
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