December 15, 2022

expert reaction to study looking at intermittent fasting and type 2 diabetes

A study published in the Journal of Clinical Endocrinology & Metabolism looks at the effect of an intermittent calorie-restricted diet on type 2 diabetes remission.

Prof Victor Zammit, Professor of Metabolic Biochemistry, University of Warwick, said:

“Remission of T2DM after adherence to very low calorie diets has been well established.  This paper describes the use of a regimen of widely spaced meals during a 24h cycle, as opposed to grazing and ‘chaotic’ food intake.  This approach seems to have some similar beneficial effects in terms of remission in T2DM patients.  Previous work at Warwick has established the mechanism through which the spacing of meals could be working, namely by allowing insulin levels to reach basal levels between meals.  As we have shown that the effect of insulin on the liver depends on the insulin-status, allowing the insulin levels to decrease to basal before subsequent insulin spikes mediated by eating enables the liver to respond to meal-induced insulin secretion with inhibition of liver fat accumulation  and secretion – both of which contribute to the metabolic syndrome that accompanies T2DM.  Beneficial effects of structured feeding regimens on blood lipids in humans has been demonstrated in previous trials on obese women.”

Prof Tom Sanders, Professor emeritus of Nutrition and Dietetics, King’s College London, said:

“This is a relatively small study and the main problem is that weight loss was much greater in those allocated to intermittent fasting.  This is not surprising but a proper comparison would be with individuals who reduced their food intake uniformly over time to the same degree as those doing intermittent fasting.  The bottom line is that if obese/overweight persons with diabetes lose substantial amounts of weight their diabetes is likely to go into remission.  This study does not show that intermittent fasting is superior to uniform caloric restriction.”

Dr Duane Mellor, Registered Dietitian and Senior Lecturer, Aston Medical School, Aston University, said:

“Although there have been studies to show low calorie diets and low carbohydrate diets can help people with type 2 diabetes achieve remission, this relatively small study is the first to show the use of intermittent fasting – where for five days people ate only 840kcal per day and for the following 10 days they ate according to their appetite following the Chinese dietary guidelines for a total of 3 months.  This was compared to a group who were told to eat according to their appetite (no calorie restriction) following the Chinese dietary guidelines.  So, this study did not compare two diets with the same energy intake as the intermittent diet was about 75% of energy intake compared to normal intake.  Therefore there is no surprise that the intermittent diet group lost weight (almost 6kg on average or about 10% of starting body weight).  As one of the best predictors of achieving remission in type 2 diabetes is weight loss, it is impossible to say if it is intermittent fasting which is helping to induce remission as it is most likely to be the result of the weight loss.  If people with type 2 diabetes are thinking about changing their diet or wonder if they might be able to put their diabetes into remission, it is important that they speak to the diabetes health professional and discuss the potential effects of changing diet on their medication to minimise risks for example hypoglycaemia.  There is no one best dietary approach to manage type 2 diabetes or bring about remission, it is the diet that is most suitable for that individual living with type 2 diabetes.”

Prof Keith Frayn, Emeritus Professor of Human Metabolism, Emeritus Fellow at Green Templeton College, University of Oxford, said:

“This study reinforces the message that Type 2 diabetes is a reversible condition, and shows that remission is possible in those with diabetes of relatively long duration.  The use of intermittent fasting as a means of reducing body weight to induce diabetes remission is new, and may prove useful as it seems the participants found it easy to follow this strategy.  However, it seems probable that the beneficial effect on the diabetes is primarily due to the loss of weight, as has now been shown in several studies, rather than any specific effect of the intermittent fasting protocol.  A different experimental design would be needed to support any claim that intermittent fasting has beneficial effects beyond loss of body weight.”

‘Effect of an Intermittent Calorie-restricted Diet on Type 2 Diabetes Remission: A Randomized Controlled Trial’ by Xiao Yang et al. was published in the Journal of Clinical Endocrinology & Metabolism at 14:00 UK time on Wednesday 14 December 2022.

DOI: 10.1210/clinem/dgac661

Declared interests

Prof Tom Sanders: “No conflicts of interest.”

Dr Duane Mellor: “No conflicts of interest.”

Prof Keith Frayn: “I have no conflict of interest to declare.”

For all other experts, no reply to our request for DOIs was received.