Gastric band surgery should be made more widely available, researchers say, after a study found the procedure had major benefits to moderately overweight people with type-two diabetes.

The Monash University study involving 45 people compared one group who received medical care combined with gastric banding to another that only received medical care.

Both groups also received help with exercise and healthy eating.

Gastric, or lap band, surgery involves the placement of a band around a part of the patient's stomach, limiting the amount of food they eat by making them feel more full more quickly.

It found the gastric band group lost an average of 12.2 per cent of their body weight, compared with 1.8 per cent in the medical care-only group.

Almost a quarter of the gastric band group showed diabetes remission at five years, compared to nine per cent of the medical care-only group, the study said.

In the past, research into lap-band surgery has only focused on obese people.

Current guidelines recommend surgery be reserved for people with a body mass index (BMI) higher than 35, whereas those involved in this study had a BMI of 25-30.

Lead researcher Dr John Wentworth said those who had gastric or lap band surgery had a reduced risk of diabetes-related health problems and their need for medication, and it dramatically enhanced their quality of life.

"They were more energetic, they were happier, they had fewer aches and pains, they were delighted to throw away some medications," he said.

Body tries to 'defend' itself against weight loss

Dr Wentworth said while dropping a few kilograms made a huge difference to people with diabetes, the body often defended itself against weight loss.

"Even if you're a little bit overweight and you lose weight, and you sustain that weight loss, it really has a dramatic benefit for your diabetes," he said.

"[But] our body tends to defend its weight once we become overweight.

"It pushes the appetite up, it gets you using less energy and it really does try and drive you up to that weight you started at, and we really don't know why that happens."

He said because of this, at the moment the most effective strategy for weight loss was surgery.

"I think this study contributes to a very large and very compelling field of research, which really does make the argument that weight loss surgery is an effective diabetes treatment and that perhaps we are not utilising it as much as we could," he said.

According to researchers, gastric band surgery and aftercare costs about $13,910 per patient, but Dr Wentworth said it was offset by the savings made from the improvements to long-term quality of life.

About 1.7 million Australians have diabetes, costing an estimated $14.6 billion a year, according to Diabetes Australia.