GLOBALLY, the incidence of diabetes is increasing, and is expected to rise to 578 million in 2030. This is a result of increasing incidence of both Type 1 diabetes (T1D) and Type 2 diabetes (T2D). There are three main symptoms associated with T2D, including excessive glucagon secretion, insulin resistance, and insufficient insulin secretion. Individuals with T2D often also have elevated bodyweights, heightening the problem.
Previous studies have suggested fasting is beneficial for healthy and diseased individuals, including metabolic disorders such as diabetes. Fasting-induced energy deficit could aid with permanent weight loss in people with T2D, and help to prevent T2D in individuals with obesity who are at high risk. Therefore, the research team sought to provide an overview of the safety and efficacy of various fasting interventions in people with T1D and T2D, and to provide a basis for fasting in diabetes.
In September 2022, a narrative, non-systematic review of the literature was conducted by searching PubMed. A total of 97 potentially relevant studies were considered for the review.
The authors observed some substantial benefits of fasting for patients with T1D and T2D. Specifically, in individuals with T1D, fasting was linked with a reduced risk of hypoglycaemia, lower glycaemic variability, and improve fat metabolism. T1D therapy adjusts glycaemia with exogenous insulin, dietary changes, and exercise. However, in cases of longstanding T1D, insulin resistance can worsen, resulting in excessive weight gain. Therefore, authors stress that when fasting with T1D, insulin adjustments should be carefully accounted for, ensuring the time spent in hypoglycaemia remains unaffected.
Despite the benefits of fasting, it could adversely affect body composition and the cardiometabolic system. This is particularly relevant during Ramadan fasting, where the incidence of severe hypoglycaemia among individuals with T1D increases. This population should be aware of diabetes self-management principles, such as continuous glucose monitoring. Lastly, the authors suggest fasting could be an appropriate intervention for pre-diabetes management, in which targeted lifestyle and weight loss interventions are very beneficial.
Overall, the current review showed that individuals with T1D and T2D may fast without risking severe glycaemic disturbances. However, it is only an efficient therapy for diabetes when performed along with glucose monitoring. These considerations are of utmost importance to patients with diabetes who fast over a prolonged time, for example during Ramadan.