Study into low-calorie diets to tackle Type-2 diabetes

Researchers are investigating whether low-calorie diets should be offered as a treatment option to put Type 2 diabetes into remission.

A £2.4 million research project funded by Diabetes UK will be carried out by researchers at Newcastle University and the University of Glasgow.

It aims to answer the question of whether losing weight on a low calorie liquid diet and keeping it off using a structured, personalised support programme is a viable treatment for putting Type 2 diabetes into remission in the long-term.

It will see 140 people with Type 2 diabetes spend between eight and 20 weeks consuming just 800 calories per day, mainly in the form of nutritionally-complete formula shakes. Then, as normal meals are reintroduced, they will learn how to change their lifestyles permanently.

Participants will be monitored over the next two years and their results will be compared to another 140 people who have not followed the diet but have instead followed what is currently accepted as the best advice for managing weight. As well as monitoring the long-term effects of the diet, some of the participants will have MRI scans, which will show researchers what is happening inside the body during the diet.

This will be the largest single research project Diabetes UK has ever funded in its 79-year history. It follows a study from 2011 that found that 11 people with Type 2 diabetes who spent eight weeks on a low-calorie liquid diet all saw their insulin production return to normal and their Type 2 diabetes put into remission. These findings backed up anecdotal reports and results from bariatric surgery to raise the prospect of transforming the way Type 2 diabetes is treated.

But because the 2011 study was designed to better understand the biological processes in the body and only followed its participants for a relatively short period of time, scientists do not yet understand the long-term effect of these diets. This is why a longer and larger study is needed to find out whether the benefits of following such a restrictive diet outweigh any adverse effects. Also, the 2011 study was carried out in a research setting and so it is unclear whether such diets can be transferred to a larger scale as part of routine GP care, where large numbers of overweight people with Type 2 diabetes are managed in the UK.

Because of these unanswered questions, Diabetes UK does not yet recommend low-calorie liquid diets to people with Type 2 diabetes. But the charity is confident that the new study will answer these questions and so give the NHS enough evidence to make a decision on whether low-calorie diets should be offered as a routine treatment option.

Professor Mike Lean, the lead researcher at the University of Glasgow, said: “The reason for doing this research is that we do not know whether the extra effort, and possible stress, of following a very restrictive diet for several months will indeed bring benefits in the long term. Although benefits are possible, we know that weight regain after liquid diets has been common in the past, and could have harmful effects. This is why we need to study sufficient numbers of people for long enough to be sure that the benefits outweigh the costs.

“Following the huge media interest in the 2011 study, many people might think they want this kind of treatment, but first we need to prove it actually works in routine clinical practice. If our analysis shows that this approach to weight loss and weight management is both clinically effective and cost-effective, we would aim to produce a programme that can be implemented in the NHS as soon as possible.”

Dr Matthew Hobbs, Head of Research for Diabetes UK, said: “Type 2 diabetes will always be a serious health condition but perhaps it won’t always be seen as a condition that people have to manage for the rest of their lives and that worsens inevitably over time. The 2011 study and evidence from bariatric surgery has shown us that it can be put into remission. 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.

“As exciting as those findings were, there is still so much about low-calorie diets that we do not yet understand. We don’t know whether this diet will put Type 2 diabetes into remission in the long term. Even more fundamentally, this kind of diet is certainly not an easy option or a ‘quick fix’. People will still have to maintain a healthy lifestyle to stop their Type 2 diabetes coming back. We are also talking about consuming so few calories that people taking part are likely to feel hungry quite a lot of the time and there are real questions about what proportion of people will be able to stick to this for the length of time needed for it to be effective.

“Until these questions are answered, we are not in a position to recommend that people with Type 2 diabetes follow this type of diet, or to advise the NHS to offer it as a treatment option. That uncertainty is exactly why we are supporting these researchers with this grant. This new study should provide the evidence we need in order to give definitive answers to these questions.”

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First published: 16 January 2014

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