Weight-loss jab users urged to strength train or face ageing 10 years, experts warn

Weight loss jab users face muscle loss comparable to “ten years of ageing” if they don’t strength train, researchers have warned.

Drugs such as Mounjaro and Wegovy not only cause rapid fat loss but lean muscle loss too – in similar levels seen following bariatric surgery, during cancer treatment or approximately ten years of ageing.

Muscle and bone mass loss associated with weight loss drugs may also increase frailty and risk of falls in older adults, which costs the NHS £2.3bn every year.

But exercise, especially strength training, has been shown to limit muscle mass loss that accompanies significant weight loss.

It’s estimated that 2.5 million people in the UK are using weight loss drugs. Dr Matthew Wade, interim director of Research at UKActive, a fitness non-profit, has highlighted the risks of not exercising during treatment.

“The rapid rollout of GLP-1 has shown dramatic results for patients but in order to avoid weakening the body, there are simple and effective strength exercises which are essential for sustainable results,” Dr Wade said.

“The health and fitness sector can support people taking weight loss medications, but we want to see the Government go further by working with the fitness, nutrition and pharmaceutical industries to deliver the critical wraparound support patients need,” he added.

A report by Les Mills and UKActive has called for UK gyms to work with the government to tailor programs for those taking weight loss drugs.

Weight-loss injections, also known as GLP-1 receptor agonists, work by mimicking the natural hormone which regulates blood sugar, appetite and digestion – leading to a decreased calorie intake and as a result weight loss.

The NHS and NICE also say weight loss drugs should be taken alongside dietary changes and exercise.

“Regular strength training is vital to our health at all stages of life, but the research suggests this is especially true for people taking weight loss medications,” Bryce Hastings, head of research at Les Mills, said.

“In addition to strength training two to three times a week, it’s recommended that people taking weight loss medications accumulate 150 minutes of moderate to vigorous physical activity per week. Studies have shown this helps continue fat mass loss in the weight maintenance phase of treatment and lessen weight regain after treatment has stopped.”

Mr Hastings said more research is needed to deeper understand the relationship between weight loss medications and strength training, but added recommendations in the report highlight practical next steps to better support the growing number of people taking weight loss medication.