Type 2 diabetes: How intermittent fasting could help reverse the condition

For the study, researchers recruited 72 participants ages 38 to 72 years old. Each had type 2 diabetes for 1–11 years and a body mass index (BMI) of 19.1–30.4.

For context, a BMI score of 18.5–24.9 is considered “healthy,” while a BMI between 25 and 30 is overweight, and 30 and above is obese. However, the BMI scoring system is not always the best indicator of a person’s overall health.

Participants were then split into two groups of 36 and were assigned either an IF regimen or regular unrestricted eating. The intervention period lasted for 3 months and included six cycles of 15 intervention days.

In each cycle, participants were assigned a specific, modified fasting diet for 5 days, in which they consumed a total of 840 calories across morning, afternoon, and evening meals. During the following 10 days, they ate as much as they wanted of what they wanted, similar to the control group.

Diets during the modified fasting days followed the Guidelines for Diabetes in China and included foods high in fiber that were low glycemic index carbohydrates.

Participants were examined at baseline, immediately after the 3-month intervention, and again at a 3- and 12-month follow-up. They continued to take their initially prescribed anti-diabetic medications throughout the study and maintained their usual exercise habits.

After the 3-month intervention, 18 of the 36 in the IF group and one person in the control group no longer needed their medications to control their diabetes.

The mean body weight of participants in the fasting group also fell by 5.93 kilograms (kg), while those in the control group experienced a weight loss of 0.27 kg.

Quality of life scores also significantly increased among those in the IF group and decreased in the control group.

At the 12-month follow-up, 16 of the 36 in the fasting group maintained diabetes remission. None in the control group were in remission.

Weight loss and quality of life in the fasting group also remained similar at 12 months.

Overall, the researchers noted that participants who were prescribed fewer anti-diabetic medications at the beginning of the study were more likely to achieve diabetes remission.

To understand how intermittent fasting may reverse type 2 diabetes, Medical News Today spoke with Courtney Peterson, Ph.D., associate professor at the Department of Nutrition Sciences at the University of Alabama at Birmingham.

Dr. Peterson was not involved in the present study but noted that intermittent fasting may reverse T2D by helping people lose weight.

“What we’ve learned over the past decade is that if people lose weight very rapidly — by eating the equivalent of about one meal per day — about 45% of people in the early stages of type 2 diabetes are able to get off all their medications and reverse their diabetes. Losing weight rapidly rids the body of fat that accumulates in the liver, pancreas and in our muscles, and this helps our pancreas to produce more insulin- which lowers blood sugar — and also helps the liver and muscle do they job of regulating our blood sugar.”

– Courtney Peterson, Ph.D., professor of nutrition sciences

Felicia Steger, Ph.D., assistant professor of endocrinology, diabetes, and clinical pharmacology at the University of Kansas Medical Center, not involved in the study, told MNT she agreed that weight loss is an important factor for diabetes remission.

She added, however, that fasting might also affect blood sugar control independently of weight loss.

“Preliminary data suggest that intermittent fasting improves [how] our pancreas responds to higher blood sugar by releasing insulin,” Dr. Steger noted.

“Intermittent fasting also improves insulin sensitivity, or how well our cells respond to the insulin signal to remove sugar from the bloodstream.”

When asked which type of intermittent fasting is most suitable for those with T2D, Dr. Saint Anthony Amofah, chief medical officer, chief academic officer, and senior vice president at Community Health of South Florida, Inc. (CHI), not involved in the study, told MNT:

“I find that what is most pragmatic, and which works best for my patients is 16-hour fasting. The longer the fasting period, the more dramatic the effect on diabetes.”

Susan Renda, DNP, MSN, RN, assistant professor at Johns Hopkins School of Nursing, not involved in the study, agreed that a few days per week of 16-hour fasting is optimal. She noted, however, that increased fasting runs the risk of the liver producing glucose, and elevating glucose levels in some.

“Medication adjustment may be needed to avoid low blood glucose or to match needs based on a different eating pattern on the fasting days,” Renda explained.

When asked the same question, Dr. Alan Reisinger III, FACP, a board-certified internist and the Associate Medical Director of MDVIP, not involved in the study, told MNT:

“In part due to individual variations in metabolism and personal preferences, there is no one approach that is consistently better than another, although the fasting-mimicking diet used in this study may have the most dramatic effect on reducing insulin levels due to its macronutrient composition and 5-day duration of fasting.”

Jesse Bakke, Ph.D., associate professor at the Department of Foundational Sciences at Central Michigan University College of Medicine, not involved in the study, agreed that intermittent fasting type should be decided on a person-to-person basis.

Bakke said that people with more advanced stages of diabetes may not be suitable for this type of fasting.

“Another consideration, rarely discussed in basic science papers, is the underlying risks to patients’ mental health. Some patients may be at an increased risk of developing disordered eating. For these reasons, it is hard to have a blanket recommendation in terms of the ‘best’ intermittent fasting regime and why I recommend personal physician input.”

– Jesse Bakke, Ph.D., assistant professor of biochemistry, cellular, and molecular biology

When asked about the study’s limitations, Dana Ellis Hunnes, Ph.D., MPH, RD, assistant professor at the Fielding School of Public Health at the University of California, Los Angeles, and author of “Recipe for Survival,” not involved in the study, told MNT:

“They only looked at one type of intermittent fasting. It was a small population sample with a low BMI and low [blood sugar levels] to begin with, making them perhaps more likely to recover than someone with a BMI of 35 and [higher starting blood sugar level].

“I’d like to see a wider sample of people with more complex cases of type 2 diabetes than this for further study. I’ll be interested to see their 5-year follow-up,” Dr. Hunnes added.

Eric Ravussin, Ph.D., associate executive director of clinical science at Pennington Biomedical Research Center, not involved in the study, noted that three people in the study had an initial BMI of 24 and that the results may therefore differ among people from the United States, who often have a BMI of 33–35 at the start of interventions.

Dr. Puja Uppal, DO, MA, board-certified family medicine physician and Founder and Chief Medical Officer of Think Healthy, not involved in the study, told MNT:

“My thought process here is that type 2 diabetes is a cardiometabolic disease that involves many body systems—kidneys, eyes, heart. For a diabetes intervention to be effective it’s important for the intervention not only to improve one’s blood sugars, but the intervention should also reduce their diabetes-related disease burden. We need to see if a diabetes intervention has actually improved a person’s overall mortality and reduced major adverse cardiac events in people with diabetes.”