Voice of Diabetes
October 23, 2020

Is crash dieting a ‘wonder cure’ for type 2?

A crash diet approach has achieved remarkable results in putting Type 2 diabetes into remission. So is this the solution that has eluded researchers for so long?

Researchers at Newcastle University, funded by Diabetes UK, have carried out a small study, which showed that putting people with type 2 diabetes on a crash diet for 8 weeks appeared to reverse their condition. Specifically, their blood glucose levels fell and their ability to produce insulin and process glucose effectively returned to a non-diabetic state.

The researchers said that the results could be explained initially by the ‘metabolic shock to the system’ of a sudden calorie deficit, and then by the reduction of fat in the pancreas and liver, which is thought to affect the production and efficiency of the insulin-producing cells in the pancreas. Participants in the study lost an average of 15.3kg on a strict low-calorie diet, or about 15% of their initial starting weight.

Weight loss surgery without the knife

The researchers say they got the idea for the study from the results being seen after weight loss surgery, which in many cases reverses type 2 diabetes symptoms. The theory has been that the surgical process produces hormonal changes in the gut, but the Newcastle team wanted to investigate if weight loss alone would have the same effect.

The team recruited 14 people who had been diagnosed with type 2 diabetes within the past four years. Three people dropped out early so 11, nine men and two women, completed it. At the outset they were all obese, with an average BMI of 33, and their average age was 49. 

For eight weeks the participants ate a diet of 600 calories a day, consisting of Optifast meal replacement drinks and three portions of non-starchy vegetables. They underwent intensive tests to measure exactly what was happening to their metabolism during the trial, which showed that they regained the blood glucose response and insulin production of a non-diabetic person.

After the trial the participants returned to eating normally and regained an average of 3.1kg in the following 12 weeks. Seven of the 11 remained free of diabetes symptoms, but three saw a recurrence of diabetes and one could not be tested for an unrelated medical reason.

Pointing out the limitations

The researchers point out that their study has several important limitations. One of course is the very small number of people in the trial, which they say was necessary to enable the very detailed ‘gold standard’ evaluation of the impact of the diet. However, the 11 that took part were in many ways typical of people who have type 2 diabetes.

The participants were fairly recently diagnosed and were not being treated with insulin or diabetes drugs that can cause hypoglycemia so it is not clear what effect this diet would have on them, or on people who have had type 2 for much longer. The follow-up period is also, so far, very short.

But is it a cure?

It is absolutely not news that losing excess weight can delay or prevent the onset of type 2 diabetes and that lifestyle measures can help control diabetes, once diagnosed, as well as drugs can. Evidence suggests that losing 5% to 10% of starting weight and keeping it off is enough to see metabolic benefits.

However what these researchers are saying is that the crash diet element is important, because it is similar to the effects of weight loss surgery, and that therefore diagnosed type 2 diabetes is potentially reversible with diet alone. This is a pretty big claim to make from a small study; there has been much more research into weight loss surgery, but this too is still relatively new, and researchers do not know whether it is a permanent solution to type 2 diabetes.

In my view, this trial is a dramatic and inspiring reminder of how beneficial losing excess weight can be if you are at risk of, or diagnosed with, type 2 diabetes. If further research bears it out, it could be the case that a supervised crash diet one day becomes an option for delaying the onset of type 2 or the need for medication.  But there are still many unknowns and it would be a shame if the headline-grabbing nature of this study gave anyone false hope.

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