By DR ELLIE CANNON, MAIL ON SUNDAY COLUMNIST AND GP
Published: 01:00 BST, 16 August 2026 | Updated: 18:55 BST, 16 August 2026
It was a shocking story and a warning for those looking to get thin quick. Last week it was reported a 19-year-old American law student living in London had died after taking a weight-loss drug containing tirzepatide – the active ingredient in NHS-approved Mounjaro.
Josephine Nasr, from California, had suffered a heart rhythm complication in her room at the University of East London in September 2025. A post-mortem examination concluded she had an undiagnosed heart condition, but also suggested a drop in blood sugar caused by the drug could have triggered the complication.
Hers is one of a growing number of deaths linked to weight-loss drugs. According to official figures, in the UK there have now been 216 people who have died due to possible side effects – though there is no way to know for sure the medicine was the primary cause, only that it was suspected.
But perhaps the most important of these cases is the death of Caroline Savage, a 73-year-old grandmother from Norfolk, because it reveals an under-discussed risk.
Caroline began taking the jab in 2024 after years of failing to lose weight. She also suffered from lipedema – a chronic condition that causes fat to build up in the legs, hips and arms, which Mounjaro has been shown to ease.
Within four months, Caroline had lost two stone. However, in October 2024 she developed severe stomach pain – before collapsing at home. She died in hospital.
What is so significant is the cause of death – faecal peritonitis, where faecal matter leaks from the intestines. It’s a condition that, until now, has not been associated with weight-loss drugs.
However, I worry that countless Britons on these medicines could be at risk. This is because we know one of the main risks is ordinarily not life-threatening: constipation.
Josephine Nasr, from California, suffered a heart rhythm complication in her room at the University of East London in September 2025
Constipation – often defined as no more than three bowel movements a week – affects around one in five adults, and a third of over-60s.
This is largely due to poor diet. Fibre is crucial for regular bowel movements, but under 5 per cent of Britons consume the recommended daily 30g. Widespread dehydration is also thought to be a cause. And growing evidence suggests weight-loss jabs can super-charge constipation. This is because they slow down the gut, meaning it takes longer for the body to expel food.
Over time, this can cause the bowels to get backed up, which puts pressure on the bowel lining and raises the risk of a rip occurring and faeces entering the intestines. This is even more of a risk for older people.
It’s possible that there are thousands of weight-loss jab patients at risk. The best way to protect against constipation? Change up your diet.
