Thousands of individuals following high-protein diets, often promoted by social media influencers, are at risk of developing incurable organ failure, experts have warned. The trend, fueled by promises of weight loss and muscle gain, has led to a significant increase in the consumption of protein products like shakes, bars, and powders. A 2024 study indicated that 56% of UK consumers actively seek protein-rich foods.
While high-protein diets are generally safe for most people, experts caution that approximately 10% of the population may be at risk of developing life-threatening kidney disease. This condition is often referred to as a 'silent killer' because it typically shows no symptoms until the kidneys begin to fail, meaning many individuals could be suffering from it unknowingly. Health professionals advise that most people should avoid consuming protein above the recommended daily intake.
Dr. Carl May, a kidney expert at the University of Bristol, explained that protein places significant stress on the kidneys as they process it. "So consistently eating above the recommended amount is going to be tough on them," he stated. "For around nine out of ten people, this won’t lead to anything serious. But that unlucky 10% could be quietly damaging their kidneys without realising it." He added that this can lead to kidney failure, potentially requiring an organ transplant.
Protein is essential for bodily functions, including repairing and building muscle, organs, and connective tissue, as well as regulating hormones and boosting immunity. It is found in both animal products like chicken, fish, and eggs, and plant-based sources such as lentils, chickpeas, and nuts.
The National Health Service (NHS) recommends adults consume about 0.8 grams of protein per kilogram of body weight daily, translating to approximately 55g for the average man and 45g for the average woman. However, some influential figures, such as Dr. Peter Attia with over three million social media followers, advocate for intakes of 2g per kilogram per day, deeming current guidance insufficient for maintaining muscle mass, especially in later life.
Retailers have also capitalized on this trend, with supermarkets launching 'High-Protein' ranges. M&S introduced products like protein-rich sandwiches and milk, while Tesco, Aldi, Lidl, and Iceland have also promoted similar items.
Experts strongly advise against adopting a high-protein diet without medical consultation. Growing evidence suggests that exceeding recommended protein levels can be detrimental to individuals predisposed to kidney disease, a condition affecting over eight million Britons, with nearly half remaining undiagnosed. Symptoms of advanced kidney disease, such as fatigue, swollen joints, itchy skin, and frequent urination, appear only when the organ is severely damaged.
Research indicates that kidney disease treatment costs the NHS over £1.4 billion annually. Dr. May noted that a genetic mutation can make some individuals' kidneys more susceptible to damage from excess protein, leading to scarring and lasting harm. "The problem is that no one knows they carry this gene until they get kidney disease," he said.
Studies have shown that for kidney disease patients, continuing a high-protein diet significantly increases the likelihood of requiring dialysis or a transplant. A recent Israeli study found that kidney disease patients consuming slightly more protein than the UK average were about a third more likely to develop the most severe form of the condition.
Individuals with diabetes and high blood pressure are identified as the most vulnerable to kidney disease. The number of kidney disease patients in the UK is projected to rise by 400,000 in the next decade, largely due to the obesity crisis contributing to increased rates of diabetes and high blood pressure.
Early detection through a blood test, known as an eGFR check, can help halt the progression of kidney disease with medication. Fiona Loud, policy director at Kidney Care UK, emphasized the importance of individuals with high blood pressure or diabetes requesting kidney function tests from their GP, noting that over a million people in the UK have undiagnosed chronic kidney disease.