Researchers at Imperial College London found that patients lost on average 4.4kg after receiving a hormone treatment.

The findings from the study also showed improvements in patients' blood glucose, with some falling to near-normal levels.

It is estimated that one in four British adults is obese, with some undergoing a procedure called a gastric bypass to keep their weight down and improve blood sugar levels in diabetics.

But the surgery can lead to complications such as abdominal pain, chronic nausea, vomiting and debilitating low blood sugar levels.

Imperial College London's previous research suggested that one of the reasons a gastric bypass worked well was because three hormones from the bowels are released in higher levels.

This hormone combination, dubbed GOP, reduces people's appetite, causes weight loss and improves the body's sugar absorption.

Researchers sought to discover if infusing patients with GOP hormones to mimic gastric bypass surgery would help weight loss and cut back high glucose levels.

A total of 15 randomly obese pre-diabetic and diabetic patients received the GOP treatment for four weeks, via a pump that slowly injected the mixture under the skin for 12 hours a day.

Patients were also given advice on healthy eating and weight loss from a dietitian.

Imperial College London said that patients on the GOP treatment lost an average of 4.4kg, compared with 2.5kg for 11 participants receiving a salt water placebo.

The GOP treatment was reported to have had no side effects.

Researchers also recruited 21 patients who had undergone bariatric surgery and 22 patients who followed a very low-calorie diet to compare the results of the GOP trial.

Those who received bariatric surgery lost 10.3kg while those following the very low-calorie diet lost 8.3kg, the experts said.

Tricia Tan, Professor of Practice (Metabolic Medicine & Endocrinology) at Imperial College London and lead author of the study, said: "Obesity and type 2 diabetes can lead to very serious and potentially life-threatening conditions such as cancer, stroke and heart disease.

"There is a real need to find new medicines so we can improve and save the lives of many patients.

"Although this is a small study, our new combination hormone treatment is promising and has shown significant improvements in patients' health in only four weeks.

"Compared to other methods the treatment is non-invasive and reduced glucose levels to near-normal levels in our patients."

Professor Tan said that although the weight loss using the GOP infusion was smaller, it was preferable to bariatric surgery due to having fewer side effects.

"This result shows that it is possible to obtain some of the benefits of a gastric bypass operation without undergoing the surgery itself.

"If further trials are successful, in future we could potentially give this type of treatment to many more patients."

The research was published in the journal Diabetes Care.

Australian Associated Press