An anti-obesity medicine called tesofensine has been found to be about twice as effective as any previous diet drug.
The drug made by NeuroSearch of Copenhagen, Denmark, was tested on some people who weight more than 100 kilograms.
A research article in the journal The Lancet suggests that those who took the drug lost almost 13 kilograms in 6 months.
The drug makes people feel full early in a meal by increasing the pleasurable effects of three neurotransmitters.
However, larger trials to come will delay its approval, reports New Scientist magazine.