People on weight loss drugs are not receiving crucial dietary support, leaving them at risk of nutritional deficiencies that could lead to serious health problems, experts have warned.
Around 1.5 million people in the UK are currently using GLP-1 drugs, including popular jabs Mounjaro and Wegovy. But many of those could be “replacing one set of health problems with another” through “preventable nutritional deficiencies,” researchers said.
A review of data conducted by academics from the University of Cambridge and University College London (UCL) found as much as 40 per cent of total weight lost during treatment with the jabs is actually lean body mass – including muscle.
Their findings, published in the journal Obesity Reviews, suggested a “real risk” of alternative health problems brought on by poor nutrition, including fatigue, hair loss and osteoporosis. They also warned a loss of mean mass can increase the risk of weakness, injury and falls.
GLP-1 receptor agonists work by mimicking the naturally-occurring hormone glucagon like peptide-1 (GLP-1) released into the blood in response to eating. The drugs suppress appetite, increase a feeling of being full, and reduce food cravings.
But researchers said while this is effective for a 16 to 39 per cent reduction in calorie intake, there has been little research to examine their impact on diet quality.
The team analysed 12 studies of adults taking GLP-1 medications, and found only three involved nutrition professionals. In addition, one observational study found widespread nutrient inadequacies and limited access to dietetic support.
They warned medics are facing a “missed opportunity” to support long-term health as well as weight loss goals by failing to provide appropriate advice.
Research leader Dr Marie Spreckley, from the University of Cambridge, said: “Use of GLP-1 receptor agonist therapies has increased rapidly in a very short period of time, but the nutritional support available to people using these medications has not kept pace. Many people receive little or no structured guidance on diet quality, protein intake, or micronutrient adequacy while experiencing marked appetite suppression.
“If nutritional care is not integrated alongside treatment, there’s a risk of replacing one set of health problems with another, through preventable nutritional deficiencies and largely avoidable loss of muscle mass. This represents a missed opportunity to support long-term health alongside weight loss.”
It comes as the numbers of Britons taking up private prescriptions for weight loss medications soars. Of the estimated 1.5 million people in the UK using GLP-1 drugs, the vast majority – around 95 per cent– are thought to access the medication privately, according to experts.
Dr Adrian Brown, an NIHR Advanced Fellow from the Centre of Obesity Research at UCL, and the study’s corresponding author, said that while weight loss jabs can be “highly beneficial” for those living with obesity, a lack of nutritional guidance could leave people lacking in essential nutrients.
“Without appropriate nutritional guidance and support from healthcare professionals, there is a real risk that reduced food intake could compromise dietary quality, meaning people may not get enough protein, fibre, vitamins, and minerals essential for maintaining overall health,” he said.
Researchers previously warned weight-loss jab users face muscle loss comparable to “10 years of ageing” if they don’t strength train.
The study also follows warnings from the Royal College of Physicians (RCP), who said that weight loss injections alone will not make lasting progress in tackling the obesity epidemic.
“Medication alone will not be enough to make meaningful and lasting progress on tackling obesity,” the College said in a new position statement, adding that the government must also tackle the “social and environmental drivers of obesity”.
Dr Kath McCullough, special adviser on obesity for the RCP, said that while weight loss drugs can be “part of the solution for some patients”, efforts should focus on preventing people developing obesity and overweight in the first place.
