Protein is having a moment, the shelves of supermarkets and health stores are groaning under the weight of shakes and bars. It is estimated that around one in ten people in the UK eat a protein bar once a week – while a similar number regularly consume protein powders.
And cost doesn’t seem to be an obstacle. Check out the protein shakes sold at Joe and the Juice, a chain of coffee and juice bars. It reported record profits of £45m last year, helped by the introduction of protein shakes.
His latest Beets and Berries protein shake (which contains strawberries, beetroot powder, banana, date puree, collagen, whey protein and ‘sproud m*lk’ (a milk alternative made from pea protein and canola and oat oil) costs £9. instance.
Protein is vital for energy, growth, tissue repair and maintenance of our body, especially bones and muscles.
Joe and the Juice reported record profits of £45m last year, helped by the introduction of protein shakes
It supports the function of organs such as the brain, heart and liver. It also plays a vital role in maintaining aspects of normal body function: for example, our antibodies, an essential part of the immune system, and hemoglobin, which carries blood around the body, are both proteins. Too little protein could affect your immunity and how quickly or well wounds heal.
So should we all be following the trend of protein shakes and bars – literally – to increase our intake?
The risks (which include kidney stones and tooth decay) may outweigh the benefits if you overdo it.
The average adult already has more than the recommended levels of protein (45g a day for women, 55g for men) – women eat 67g a day and men 85g, according to the government’s National Diet and Nutrition Survey.
And it’s not hard to see why.
For example, to eat the recommended amount of protein per day, a woman could have one egg (6g) for breakfast; 6 ounces of plain Greek yogurt at lunchtime (18 g); snack on a handful of nuts (4g); and 2 oz of cooked chicken for dinner (14 g) and coffee with milk (3 g).
The demands of athletes and regular gym goers may be a bit higher as your body needs protein to repair and grow the muscles that are broken down during exercise.
“It’s about 1.2g to 2g more per kilogram of bodyweight per day for endurance training and muscle preservation – and about 1.6 to 2.8g more per kilogram of bodyweight per day during the strength-building period,” he says Dr Nicolas Berger, Senior Lecturer in Sport and Exercise Science at Teesside University. So if you weigh 60kg (9.4lbs), you’ll need about 100g more protein to build strength.
And it’s not just regular exercise that means your need for protein increases, it’s just getting older that means you need more to maintain muscle strength.
According to a 2020 University of Sheffield study, older people need around 1.2g to 1.5g of extra protein per kg of body weight per day. They should consume 25-30g of protein in each of their three daily meals.
The demands of athletes and regular gym goers may be a bit higher as your body needs protein to repair and grow the muscles that are broken down during exercise.
This is to prevent muscle wasting, which in turn can help prevent falls and general frailty, as well as certain conditions such as pressure ulcers, and speed recovery after surgery – too little protein can affect wound healing and your ability to fight infection.
The optimal way to get protein, experts say, is from whole food sources, in part because many protein-rich foods are important sources of other nutrients.
“In general, it’s better to get your protein from natural sources such as beans, legumes, soya, nuts, fish, eggs and meat,” says Lucy Jones, nutritionist and chief clinical director at NHS weight care provider Oviva.
“These foods provide protein and other essential nutrients, including fiber, vitamins, minerals and healthy fats.
‘Choosing whole foods for protein intake ensures a more balanced intake of all the nutrients that are often missing when taking protein supplements.’
However, another concern with protein bars and shakes is their added ingredients such as sweeteners and sugars.
“Protein bars and drinks claim to provide a convenient way to increase or maintain protein intake, aid muscle recovery, promote weight loss or gain muscle—and even claim to be a complete meal replacement,” says Dr. Berger.
“But that’s not always true, and they often have very little quality protein.” [i.e. a type that doesn’t provide all nine essential amino acids needed for muscle production or is in a form that can’t easily be used by our cells] – as well as many other low-quality added ingredients.”
Common additives of concern include artificial sweeteners such as sorbitol and mannitol, which can cause bloating and indigestion.
“The common thickener carrageenan is associated with inflammation, while the stabilizers guar gum and xanthan gum can cause digestive distress in sensitive individuals,” she adds.
“Such ingredients also make these options ultra-processed foods (UPFs)—foods that have been linked to weight gain and, increasingly, diseases such as type 2 diabetes.
“As such, it could overshadow any health benefits.”
Dr Nicolas Berger, Senior Lecturer in Sport and Exercise at Teesside University
And then there’s sugar. “A lot of protein bars contain sugar to make them taste better,” says Raggi Munjal, a dentist based in South Yorkshire.
“So if you have these bars regularly – like one a day – they can cause tooth decay like any chocolate bar, because of the sugar attack on the teeth.”
They are also often high in calories for what is essentially a snack rather than a proper meal, which can increase unhealthy weight gain. (For example, the Joe and the Juice Beets and Berries Protein Shake contains 371 calories.)
“And the irony is that it’s not necessary to have an excess of protein – even if you’re athletic,” adds Jon Dearing, consultant orthopedic surgeon at Carrick Glen Hospital in Ayr, who specializes in sports injuries.
“Excess protein will simply be removed without being broken down or used by our cells.”
However, too much protein can overwhelm this process. As Bhaskar Somani, professor of urology at University Hospital Southampton, explains, it can hinder kidney function and lead to kidney stones: pebble-like pieces of minerals. This occurs when there are too many waste products in the body and too little fluid to flush them out, which can then combine with calcium in the urine to form stones.
“Stones can block the ureters – the tubes from the kidneys to the bladder – leading to infection, and if left untreated and unrecognised, can even cause loss of kidney function and even kidney failure,” says Professor Somani.
“I have had several young patients come to me with kidney stones with no previous medical history. And when I ask about their lifestyle, I find out that they have protein shakes. The fastest I’ve seen a patient develop a stone after starting it was six weeks!”
Meanwhile, earlier this year researchers at the University of Pittsburgh found that eating more than a fifth of your calories from protein can activate a type of white blood cell that can in turn clog arteries with plaque, a substance that damages vessels and impairs blood flow. .
Poor blood flow is associated with a higher risk of stroke and heart attack.
So does anyone really need protein shakes?
Dr Tom Crisp, consultant in sports and exercise medicine at Queen Mary University of London, is unequivocal. “The biggest scam is the hype surrounding protein shakes and bars.
“Our daily requirement is about one 8oz steak. Anything more than that is just an expensive way to make you pee more often.”
This is because excess protein is excreted from the body through urine, which makes us go to the toilet more.
“If you’re doing, say, competitive weightlifting, you might need a little more—but not a lot,” he adds.
Dietitian Helen Bond, spokeswoman for the British Dietetic Association, agrees.
“Most people have enough protein in their diet – it’s a myth that we need excessive amounts. It’s just band-wagoning. Yet we are sold on the idea that we should pay a premium for it.”
Joe and the Juice did not respond to a request for comment.