A combination of anti-addiction drugs, dieting and exercise has successfully helped people to lose weight.
Over the period of a year, a group of obese patients - who took part in the weight loss study - managed to shed up to 6% of their body weight.
According to the US researchers, the results of the study are "clinically meaningful" and may help in reducing the risk of death. The findings were published in the Lancet medical journal.
Although the treatment showed positive results, its success was weakened by a lack of significant reductions in blood pressure and cholesterol levels.
About 1,742 patients in the 18-65 age group participated in the 56-week trial, however, only half of the total number continued until the end of the study.
The experts randomly prescribed either a combination of the drugs naltrexone and bupropion or "dummy" placebo pills to the participants.
Naltrexone is commonly used to treat alcoholics and heroin addicts, while bupropion is better known as the anti-smoking drug Zyban. Both are known to affect appetite and reduce food cravings.
At the same time, the trial patients were given advice on lifestyle changes which included cutting down on calorie consumption and increasing exercise levels.
Patients had an average weight of around 100 kilograms (15.7 stone) at the start of the study. Their body mass index (BMI) averaged 36, classifying them as clinically obese.
The findings showed that treated participants lost between 5% and 6% of their body weight, depending on which of two doses of naltrexone they were given. In comparison, patients in the placebo group lost 1.3%.