Efficacy of Fasting in Type 1 and Type 2 Diabetes Mellitus: A Narrative Review

Nutrients. 2023 Aug 10;15(16):3525. doi: 10.3390/nu15163525.


Over the last decade, studies suggested that dietary behavior modification, including fasting, can improve metabolic and cardiovascular markers as well as body composition. Given the increasing prevalence of people with type 1 (T1DM) and type 2 diabetes mellitus (T2DM) and the increasing obesity (also in combination with diabetes), nutritional therapies are gaining importance, besides pharmaceutical interventions. Fasting has demonstrated beneficial effects for both healthy individuals and those with metabolic diseases, leading to increased research interest in its impact on glycemia and associated short- and long-term complications. Therefore, this review aimed to investigate whether fasting can be used safely and effectively in addition to medications to support the therapy in T1DM and T2DM. A literature search on fasting and its interaction with diabetes was conducted via PubMed in September 2022. Fasting has the potential to minimize the risk of hypoglycemia in T1DM, lower glycaemic variability, and improve fat metabolism in T1DM and T2DM. It also increases insulin sensitivity, reduces endogenous glucose production in diabetes, lowers body weight, and improves body composition. To conclude, fasting is efficient for therapy management for both people with T1DM and T2DM and can be safely performed, when necessary, with the support of health care professionals.

Keywords: Ramadan fasting; diabetes mellitus; fasting interventions; intermittent fasting; periodic fasting; time-restricted fasting.

Publication types

  • Review

MeSH terms

  • Behavior Therapy
  • Body Composition
  • Diabetes Mellitus, Type 1*
  • Diabetes Mellitus, Type 2* / therapy
  • Fasting
  • Humans

Grants and funding

This research received no external funding.