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Research spotlight – low-calorie diet for Type 2 diabetes

Professor Roy Taylor and Professor Mike Lean
Professor Roy Taylor (left) and Professor Mike Lean (right)

In 2013, we awarded our largest ever research grant of £2.4 million to understand the impact of a low calorie diet on Type 2 diabetes.

Professor Roy Taylor at Newcastle University and Professor Mike Lean at the University of Glasgow are comparing the long-term effects of a new weight management approach to the best diabetes care currently available.

The aim is to find out if an intensive weight management plan can help people put their Type 2 diabetes into remission for the long term.

The DiRECT study

What is the background to this research?

Not everyone with Type 2 diabetes is overweight, but weight gain and obesity are the most important risk factors for Type 2 diabetes and the reason why Type 2 has become a global epidemic that affects overweight people of all ages.

Surgical operations, such as gastric banding and gastric bypass, are potential solutions that have been shown to put Type 2 diabetes into remission for up to 80 percent of patients. These treatments are invasive and carry some risk of surgical complications, which means they're not offered to everyone.

What do we know already about low-calorie diets?

In 2011, a Diabetes UK research trial at Newcastle University tested a low-calorie diet in 11 people with Type 2 diabetes, which helped us to understand how Type 2 diabetes can be put into remission.

After the eight-week diet, volunteers had reduced the amount of fat in their liver and pancreas. This helped to restore their insulin production and put their Type 2 diabetes into remission. Three months later, some had put weight back on, but most still had normal blood glucose control.

An MRI scan of the liver shows high levels of fat in green (left) and a sharp decrease in liver fat achieved using a low-calorie diet
An MRI scan of the liver shows high levels of fat in green (left) and a sharp decrease in liver fat achieved using a low-calorie diet (right)

This study was only a first step. It was designed to tell us about the underlying biology of Type 2 diabetes, and it followed the participants for only three months.

Another study, published in 2016, confirmed these findings and showed (in 30 people) that Type 2 diabetes could be kept in remission six months after the low-calorie diet was completed. It also suggested that the diet was effective in people that had had Type 2 diabetes for up to 10 years.

Both of these studies were very small, and were carried out in a research environment. We don't yet understand the long-term effects of these diets, or how a low-calorie diet might be used to bring about and maintain Type 2 diabetes remission in a real-life setting, as part of routine GP care.

What is the aim of the current research?

The DiRECT (Diabetes Remission Clinical Trial) study aims to find out if intensive weight control can bring about the remission of Type 2 diabetes and be maintained long-term through routine NHS care.

The trial will compare the long-term effects of a low-calorie diet and weight management programme to best available care for Type 2 diabetes.

What will the research involve?

Professor Roy Taylor
Professor Roy Taylor

A number of GP practices across Scotland and Tyneside are recruiting people aged 20-65 who are overweight and have been diagnosed with Type 2 diabetes in the last six years. Participants at half of the practices will receive the current best-available Type 2 diabetes care, while those at the other half will receive a low-calorie diet for between eight and 20 weeks.

Afterwards, those on the low-calorie diet will be gradually re-introduced to normal food over a period of two to eight weeks and will receive expert support to help them maintain their weight loss in the long term.

Participants receiving best-available care will get weight loss support in accordance with the latest clinical guidelines, but won't receive the low-calorie diet.

The researchers will test metabolisms and measure fat deposits inside the body, to reveal exactly how major weight loss can put Type 2 diabetes into remission. They'll also carry out psychological assessments with the participants and healthcare professionals taking part in the study, to work out how this approach to weight management might form part of routine GP care.

Where is the research taking place?

This study will take place at around 30 GP practices in Scotland and Tyneside. The research will be carried out and the data analysed by researchers at the University of Glasgow and at Newcastle University.

Who can take part?

Only people invited to take part by their GP practice can get involved in this study. Recruitment is only taking place at selected GP practices in Scotland and Tyneside. Individual patients are not being recruited.

Professor Mike Lean
Professor Mike Lean

How will it benefit people with diabetes?

If this study shows that a low-calorie diet can safely put Type 2 diabetes into remission for the long term, it could completely transform the way this condition is viewed and treated.

If the diet can be used practically and effectively, it could lead to significant changes in the way that Type 2 diabetes is managed by the NHS. It could also help people with this condition live for longer, improving quality of life and reducing the risk of serious health complications, without the need for invasive weight loss surgery.

If a low-calorie diet can be used within routine GP care, it could ultimately be of enormous benefit to millions of people living with Type 2 diabetes in the UK.

When will results be available?

This study will last until October 2018, and the overall results will be released once all of the data has been analysed. We'll report the results in Diabetes UK publications and on the website.

The low-calorie diet

What will the diet used consist of?

The diet used in DiRECT will last for between 8 and 20 weeks and provide around 800 calories a day. It will consist of four diet soups or shakes per day, providing all essential vitamins and minerals and lots of fluids.

Will the diet cure Type 2 diabetes?

The diet being studied isn't a 'quick fix' for Type 2 diabetes. It should help people taking part in the study to lose weight – specifically, the fat in and around their liver and pancreas. This should, in turn, help to put their Type 2 diabetes into remission.

It's likely that some people who take part in the research will find the diet challenging, and every participant will have to work hard to keep weight off in the long-term to maintain Type 2 diabetes remission.

Is the diet used in this research available now?

Low-calorie diet foods are not available on prescription from the NHS. They're marketed by a range of private companies, but can be expensive and come with limited evidence of long-term benefit.

This research is the only way to tell if weight management using a low-calorie diet is practical and more effective than the current best-available treatments for Type 2 diabetes.

Should people with Type 2 diabetes follow the diet used in this research?

Until we have evidence that a low-calorie diet is more effective than the current best-available treatment, Diabetes UK recommend that people with Type 2 diabetes only attempt to lose weight in this way after they have spoken to their GP.

We're confident that DiRECT will answer important questions and give the NHS enough evidence to decide whether low-calorie diets should be offered as a routine treatment option. People with diabetes should always consult their GP before making changes to the way that they manage their condition.

What diet does Diabetes UK recommend for people with Type 2?

Diabetes UK recommends that people with Type 2 diabetes eat a healthy, balanced diet that is low in sugar, salt and fat and includes plenty of fruits and vegetables. For information on living a healthy lifestyle and eating well with Type 2 diabetes please see our guide to diabetes.

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