Many people with Type-2 diabetes will be taking the drug metformin because it helps the body respond to insulin, so stops blood glucose levels from soaring too high. In a new twist, a 15-year study of more than 30,000 people found it can also lead to steady long-term weight loss.
What’s more, it’s better than a strict diet and exercise plan. Researchers suggest metformin could be prescribed to people who are working hard and long to keep weight off, to help their efforts and keep their morale high.
The US study compared the effects of metformin to a healthy diet and exercise in people who were striving to control their weight.
Researchers at Louisiana State University, in the US, recruited 3,234 participants who were overweight, obese, or had high glucose levels. They were randomly given either a placebo, an intensive lifestyle intervention consisting of a diet and exercise plan, or 850mg of metformin twice a day.
After a year, nearly 30% of participants in the metformin group, over 60% in the lifestyle group and 13% in the placebo group, had lost at least 5% of their weight.
In years six to 15 of the study the average weight loss of participants was 6% per year in the metformin group, 4% in the lifestyle group and 3% in the placebo group.
Study co-author Professor Kishore Gadde says: “Diet and exercise enthusiasm generally doesn’t last long. Taking a pill a day is a lot easier than dieting and exercising for 15 years. Almost no one can achieve it.”
Prof Gadde thinks more research should be done on metformin’s potential use as a weight-loss management tool for people who struggle to keep the pounds off.
However, the stumbling block is that from a regulatory point of view metformin can’t be prescribed to help patients lose weight.
Neither the US Food and Drug Administration nor NHS has approved metformin for weight-loss purposes alone.
But there is a loophole. In the UK doctors can take responsibility to prescribe a drug for a purpose not included in its licence.
So some doctors may prescribe it “off label” to people who are overweight or obese and have Type 2 diabetes or prediabetes.
In Type 2 patients, metformin stops blood glucose levels rising too high. This means the body doesn’t have to produce as much insulin to keep blood glucose levels in the normal range.
With the resulting lower insulin levels, a patient’s hunger is reduced when taking metformin. They eat less and weight management is easier.