Intermittent fasting improves blood sugar control, causes weight loss in insulin-treated type 2 diabetes patients

Type 2 diabetes is a chronic disease characterized by high blood sugar and insulin resistance. The number of people affected by diabetes has increased worldwide almost five times, from 108 million in 1980 to 537 million in 2021. Estimates have revealed that 95% of diabetes people have type 2 diabetes. Widespread consensus about type 2 diabetes is that it is irreversible. However, some studies have shown that this may not be true.

Research has shown that diabetes remission can be achieved through calorie restriction and intensive lifestyle interventions. Intermittent fasting is a dietary intervention of alternate fasting and eating, which has gained popularity among people trying for weight loss. In people with type 2 diabetes mellitus (T2DM), it could be an alternative to classic calorie restriction. 

Anna Obermayer from the Medical University of Graz in Graz, Austria, and colleagues aimed to determine the safety and feasibility of 3 nonconsecutive days of intermittent fasting (IF) per week over 12 weeks in people with insulin-treated type 2 diabetes.

The study included forty-six people; they were randomized to an IF or control group. Continuous glucose monitoring and dietary counselling were provided. Coprimary endpoints included a change in HbA1c from baseline to 12 weeks and a composite endpoint of weight reduction (insulin dose reduction ≥10%, weight reduction ≥2%, and HbA1c reduction ≥3 mmol/mol).

Key findings include:

• At baseline, the 22 participants assigned to the intermittent fasting group had an average glycated hemoglobin (HbA1c) level of 69 mmol/mol (8.5%).
• Over 12 weeks, they fasted for three nonconsecutive days/week, reducing their calorie intake by 75% on these days, and ate as they wished on the remaining four days. This resulted in an average 7.3 mmol/mol HbA1c reduction, which was significant versus the change in the 24 control group participants, who continued with their usual diet and experienced an average 0.1 mmol/mol increase in HbA1c from a baseline of 66 mmol/mol (8.2%).
• There were no episodes of severe hypoglycemia during the study. Of the five serious adverse events (two in the fasting group), none were thought to be related to the intervention.
• The average daily insulin dose in the fasting group was 52 IU at baseline, which declined to 45 IU during the 12-week intervention period. In contrast, it rose from 59 to 63 IU in the control group, with the difference between the two is statistically significant.
• Bodyweight also decreased with intermittent fasting by an average of 4.77 kg from a baseline of 96 kg, which was again a significant change relative to the average 0.27 kg increase observed in the control group from a baseline of 104 kg.

Intermittent fasting three days a week over 12 weeks was linked with a lower HbA1c and more significant weight loss without an increased hypoglycemia risk compared to a standard diet.

Reference:

Anna Obermayer, Norbert J. Tripolt, Peter N. Pferschy, Harald Kojzar, Faisal Aziz, Alexander Müller, Markus Schauer, Abderrahim Oulhaj, Felix Aberer, Caren Sourij, Hansjörg Habisch, Tobias Madl, Thomas Pieber, Barbara Obermayer-Pietsch, Vanessa Stadlbauer, Harald Sourij; Efficacy and Safety of Intermittent Fasting in People With Insulin-Treated Type 2 Diabetes (INTERFAST-2)—A Randomized Controlled Trial. Diabetes Care 2022; dc221622. https://doi.org/10.2337/dc22-1622