Patients given the anti-obesity drug liraglutide, which is marketed as Victoza and given by injection, lost a stone in 20 weeks - almost twice the amount of weight loss compared to any other anti-obesity or slimming drugs tested.

The anti-obesity drug study findings, as published online in The Lancet, showed a 32 percent more patients lost 5 percent of their body weight with 3mg of liraglutide (76 percent) than orlistat (44 percent) and the placebo (30 percent).

The anti-obesity drug liraglutide injection works because it gives the patient the feeling of being full, as well as reducing the speed that food travels through the stomach.

The study, undertaken at the Department of Human Nutrition at the University of Copenhagen, Denmark observed 564 patients with a Body Mass Index (BMI) of between 30 and 40 - BMI levels that, medically, are clinically to morbidly obese.

Each patient either took a daily 3mg dose of liraglutide as well, coupled with an exercise and diet programme, 3 orlistat pills a day, coupled with the same exercise and diet programme or a placebo.

The results showed that liraglutide users lost more than 6.9 lb more than the users taking the orlistat pills and almost 10 lb more than those taking the placebo.