Scientists may be on the verge of a major breakthrough in the battle against obesity, after trials found a short-term crash diet can reverse the effects of type 2 diabetes in a matter of weeks.

The research, conducted at Newcastle University, found that putting overweight diabetics on an 800-calorie per day diet, could restore natural insulin levels and return them to health.

Type 2 diabetes, which unlike type 1 is closely linked to obesity, is thought to be caused by excess fat around the pancreas and liver which reduces insulin production.

In healthy people, the liver should only contain around 2 per cent fat, whereas this can exceed 40 per cent in obese people.

A recent report found that obesity levels of adults in developing nations have almost quadrupled to an estimated one billion since 1980, putting millions more at risk of diabetes.

Professor Roy Taylor, director of Newcastle University’s magnetic resonance imaging (MRI) centre, who led the initial study, described the early findings as “enormously exciting,” according to the Sunday Times.

“We demonstrated that by changing calorie intake we could change fat levels in the liver and pancreas and return insulin production to normal,” he said.

The technique has only been tested on 11 people so far, but it will now be tried on a further 280 people with obesity-induced diabetes as part of a £2.4m medical trial.

Professor Taylor added: “We are exploring uncharted territory and along the way there will be challenges, details to unravel, and other questions to ask. But I believe this study will lead to a quantum leap forward in our understanding of how best to manage Type 2 diabetes.”

Because the initial study only followed its participants for a relatively short period of time, scientists do not yet fully understand the long-term effect of these diets, but hope the new study will provide a clearer picture.

Dr Matthew Hobbs, Head of Research for Diabetes UK, said: If we can do this safely, on a bigger scale and as part of routine care, then following a low-calorie liquid diet would be a real game changer in terms of reducing people’s risk of devastating health complications such as amputation and blindness.”