Is Type 2 Diabetes Reversible?

Very Low-Calorie Diet and 6 Months of Weight Stability in Type 2 Diabetes: Pathophysiological Changes in Responders and Nonresponders (Diabetes Care 2016;39:808–815. doi: 10.2337/dc15-1942)

What is the problem and what is known about it so far?

Type 2 diabetes is generally thought to be an irreversible chronic condition. Studies have shown that, with worsening blood glucose control, the disease is inevitably progressive. At diagnosis, patients are told to accept having a lifelong disease. Within 10 years of diagnosis, 50% of individuals need to use insulin to control their blood glucose levels.

Why did the researchers do this particular study?

Diabetes may be reversible! Normal blood glucose control is possible after weight loss in some individuals. This happens most commonly after bariatric surgery, but it can also happen when eating dramatically fewer calories. This return to normal can happen when following a very-low-calorie diet, but researchers wanted to see if blood glucose could remain under control after a return to eating normally and maintaining weight loss for 6 months.

Who was studied?

The study included 30 people with type 2 diabetes. Some of the subjects had diabetes for a shorter time (short-duration diabetes, less than 4 years), and some had diabetes for a longer time (long-duration diabetes, more than 8 years).

How was the study done?

The study had three parts.  First, subjects were put on a very-low-calorie liquid diet for 8 weeks after stopping all diabetes medications. Next, over two weeks, they returned to solid food.  Last, the subjects spent 6 months maintaining their weight loss. Fasting blood glucose levels were measured before the diet, at the end of the diet after the return to solid food, and again after 6 months.

What did the researchers find?

Immediately after the 8-week very-low-calorie diet, 12 of 30 participants had normal (nondiabetic) fasting blood glucose levels (below 7.0 mmol/L). More importantly, after 6 months of weight loss maintenance, 13 out of 30 subjects were able to keep their fasting blood glucose level below 7 mmol/L. This means that a robust and sustainable weight loss program reversed diabetes for at least 6 months in 40% of subjects (and in 60% of subjects with short-duration diabetes).

What were the limitations of the study?

Fewer than one-half of the participants (12 of 30) were able to achieve a normal fasting blood glucose level without medication immediately after returning to a solid diet. Also, the sample size was small, and the study group represented the wider type 2 diabetes population in the northeast of England, which was predominantly white. Study of other ethnic groups is required.

What are the implications of the study?

According to these findings, type 2 diabetes is a potentially reversible condition. An intense weight loss program was able to eliminate diabetes in participants for at least 6 months. This study suggests that the disease may be solely a response to overnutrition (eating more calories than needed).  If normal fasting blood glucose levels after weight loss can be maintained in the longer term, the approach to type 2 diabetes management could change dramatically.

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