Effect of twice-weekly calorie restriction diet for glycemic control in patients with type 2 diabetes

A diet with calorie restriction two days per week was comparable to a diet with daily calorie restriction for glycemic control in patients with type 2 diabetes, according to a new study published July 20 on the Journal of the American Medical Association Network Open, the organization’s open-access publication.  

Conventional weight-loss diets with daily calorie restriction are hard to stick with over time. Intermittent calorie restriction diets can be effective for weight loss. This study examined the long-term effects of a two-day intermittent calorie restriction diet with a diet of continuous calorie restriction over 12 months for patients with type 2 diabetes.

Led by Peter Clifton, MD, PhD, of the University of South Australia in Adelaide, a team or researchers recruited 137 patients with type 2 diabetes for the randomized non-inferiority trial, who were assigned to one of two diets between April 2015 and September 2017.

According to the study, 70 patients were assigned to an intermittent calorie restriction diet (500-600 calories per day) on two nonconsecutive days with their regular diet the other five days per week. The other group of 67 patients was assigned to a daily calorie restriction diet (1,200-1,500 calories per day) for 12 months. The primary outcome measured was change in hemoglobin A1c.

The study found that the average change in hemoglobin A1c after a year was comparable between the two diets. Clifton and coauthors said there were limitations to the study, including the study population had well-controlled type 2 diabetes; medication adjustments can complicate interpreting changes in hemoglobin A1c levels; and study participants had more contact with a dietitian than is usual in a clinical setting, according to researchers.

However, overall, this preliminary study found that intermittent energy restriction is an effective alternative diet strategy for the reduction of HbA1c and is comparable with continuous energy restriction in patients with type 2 diabetes.