Take a walk and stick to healthy food. That is a far more sensible way of fighting the malady of diabetes, a group of US scientists has said.
In fact prescription drugs to prevent diabetes cannot be justified when lifestyle changes are just as effective, they stress.
Trials show rosiglitazone pills do work, but so does weight loss, which is a safer and cheaper way to avoid type 2 diabetes, the researchers argue.
In the British Medical Journal, Professor Victor Montori and colleagues, from the Mayo Clinic College of Medicine, warn against turning healthy people into patients and facing the risk of side effects at that.
Montori's comments fly in the face of a study that reported last September rosiglitazone might be as effective in preventing the onset of diabetes as in treating the disease.
Researcher Hertzel Gerstein had told the 42nd annual meeting of the European Association for the Study of Diabetes (EASD) in Copenhagen, Denmark, that people who took the rosiglitazone reduced their risk of developing diabetes by 60% in the three-year trial conducted in 21 countries.
The risk reduction was double that reported with any other drug used for diabetes prevention, and on par with reductions that had been reported in studies examining lifestyle changes alone.
Rosiglitazone is an oral drug that reduces the amount of sugar (glucose) in the blood. It is used for treating patients with type 2 diabetes.
Insulin is a hormone produced by the pancreas that is important for controlling the levels of glucose in the blood. Insulin stimulates the cells of the body to remove glucose from the blood and thereby lowers the level of glucose in the blood.
Patients with type 2 diabetes cannot make enough insulin. As a result, the cells in their bodies do not remove enough glucose from the blood, and the level of glucose rises. Rosiglitazone often is referred to as an 'insulin sensitizer' because it attaches to the insulin receptors on cells throughout the body and causes the cells to become more sensitive (more responsive) to insulin and remove more glucose from the blood.
Professor Montori and his colleagues, argue in the BMJ: 'If clinicians offer patients glitazones to prevent diabetes, they are offering certain inconvenience, cost, and risk for largely speculative benefit.
'Lifestyle changes are clearly at least as effective as glitazones and can be implemented considerably more cheaply.'
There is also a danger that offering drugs would send out the wrong message to people - that they could reduce their risk without making lifestyle changes.
Simon O'Neill from Diabetes UK said: 'Much more research needs to be done to justify the use of this drug in preventing Type 2 diabetes.
'We strongly recommend that people at risk of developing Type 2 diabetes should be incorporating increased levels of physical activity into their daily lives alongside making changes to their diet.'