High-protein diets may trigger silent kidney failure in vulnerable people.

Thousands of people following high-protein diets promoted by social media influencers face the risk of incurable organ failure, experts warn. Fitness gurus on platforms like TikTok and Instagram routinely urge followers to dramatically increase their protein intake for weight loss and muscle building. This craze has sparked a boom in protein products, including shakes, bars, and powders. A 2024 study found that 56 per cent of UK consumers are actively seeking protein-rich food and drink.

However, experts caution that while high-protein diets are safe for most, they can trigger life-threatening kidney disease for around one in ten people. This 'silent killer' condition shows no symptoms until the kidneys begin to fail, meaning many suffer without realizing it. Consequently, experts advise most people should avoid eating above the NHS-recommended amount of protein.

Dr Carl May, a kidney expert at the University of Bristol, explains that protein puts significant stress on the kidneys because the organ struggles to process it. He states that consistently eating above the recommended amount is tough on these organs. For nine out of ten people, this will not lead to serious issues, but the unlucky 10 per cent could quietly damage their kidneys. This damage can creep towards kidney failure, often requiring an organ transplant.

Experts agree that protein is a crucial component of a healthy diet. This nutrient helps repair and build muscle fibres, organs, and connective tissue while regulating hormones and boosting immunity. It can be found in animal products like chicken, beef, fish, eggs, and dairy, as well as plant-based foods such as lentils, chickpeas, tofu, nuts, and seeds.

The NHS recommends adults should eat about 0.8g of protein per kilogram of body weight per day. This amounts to roughly 55g for the average man and 45g for the average woman. Yet, in recent years, influential figures have suggested eating double or even triple this amount is a route to better health. Dr Peter Attia, who has more than three million followers, recommends aiming for 2g per kilogram per day. He has labelled current protein intake guidance as 'pathetic', arguing it is not enough to maintain muscle mass in later life.

Supermarkets have also leaned into this high-protein trend. In 2024, M&S launched a 'High-Protein' range featuring protein-rich sandwiches, yogurts, salads, snack bars, and a 'high-protein skimmed milk'. Other retailers like Tesco, Aldi, Lidl, and Iceland have also promoted high-protein products in recent years.

Despite this, experts advise against starting a high-protein diet without consulting a doctor. Growing evidence suggests that eating above NHS-recommended protein levels could be harmful for those more vulnerable to kidney disease, which affects more than eight million Britons, though around half are undiagnosed. By the time symptoms appear, including fatigue, swollen joints, itchy skin, and frequent urination, the organ is often damaged beyond repair.

Research indicates that kidney disease treatment costs the NHS more than £1.4 billion a year. Dr May notes that some individuals have a gene mutation which means excess protein can stress the kidneys. This can cause scarring and lasting damage.

No one realizes they carry the gene until kidney disease strikes. Once patients develop the condition, continuing to eat a high-protein diet significantly boosts their risk of requiring dialysis or a transplant. Recent research from Israel confirms this danger, revealing that patients who consume even a few grams more protein than the UK average face a one-third higher likelihood of progressing to the disease's most severe stage.

Experts warn that individuals with diabetes and high blood pressure face the greatest threat. The toll of kidney disease in the UK is projected to surge by 400,000 cases over the next decade, a rise largely driven by the obesity crisis that has fueled a massive spike in diabetes and hypertension.

Early detection offers a critical opportunity to halt progression through medication. General practitioners can order a simple blood test known as an eGFR check to identify early warning signs. "There are more than one million people in the UK who have chronic kidney disease without realising it," states Fiona Loud, policy director at Kidney Care UK. She urges those with high blood pressure or diabetes to demand a kidney function test from their GP immediately.