Women are more likely than men to shed the pounds if prescribed weight loss drugs – but men fare better when put on a diet, research suggests.
The study by Australian researchers analysed a number of existing studies, to identify gender differences.
The scientists found that when overweight patients with a health condition were given the weight loss drug semaglutide for more than a year, women lost an average of 18 per cent of their body weight, compared with 13 per cent for men. Two other drug studies showed similar patterns.
However, trials comparing men and women who were put on more traditional weight loss diets found men were more likely to succeed. In 10 out of 11 such studies, men lost more weight than women.
The findings, presented at the International Congress on Obesity in Melbourne, could not show why such differences emerged.
However, scientists said it was possible that women lost more weight on anti-obesity drugs because they tended to be lighter than men, so might be getting a relatively higher dose.
They said men were generally less likely than women to take part in diets as part of clinical trials – meaning that those who do might be more committed than the average slimmer.
‘The mechanisms are unclear’
The study is by Alyssa Susanto, associate professor Samantha Hocking, and colleagues in the faculty of medicine and health at the University of Sydney, NSW, Australia.
The authors said: “Gender differences in weight loss interventions with pharmacological treatment have not been studied extensively. Our findings suggest females lose more weight than males in pharmacological weight loss interventions, though the mechanisms for this are unclear. This finding is contrary to most dietary regimens where, if there is a gender difference detected, males tend to lose more weight than females.”
Men ‘more fixated on individual weight’
Researchers said men were more likely than women to take part in weight loss trials after being encouraged by their GP, and tended not to do so until their Body Mass Index (BMI) put their health in jeopardy.
Prof Hocking said: “Males tend to not perceive a problem with their weight until they reach a BMI that classifies them as severely obese or are at risk of developing weight-related comorbidities. Males are often more fixated on individual weight and BMI goals, usually recommended by their doctor.”
Professor John Wilding, past president of the World Obesity Federation and professor of medicine based at Aintree University Hospital, University of Liverpool, said: “It is interesting to note the gender differences in responses to both dietary / lifestyle and pharmacological interventions.
“One possible explanation for the greater response in females to pharmacological interventions may be that as (in general) women are lighter than men, and, when the drug doses are the same, this could result in women receiving slightly higher doses in relation to their body weight and therefore having a greater response to the drug.”
He said men who overcame their reluctance to go on a diet and did so as part of a clinical trial might be more committed than the average person.
“Men are less likely to take part in weight loss trials than women. The reasons why they don’t may be to do with stigma and reluctance to accept that they are unwell – those that do overcome these barriers and choose to take part in trials have made a big step and invested a lot to make that decision, hence they may well be more likely to stick to the advice / treatment plan offered and tend to make a really big effort to do well.”