· CDE Mehandi Sharma
Intermittent Fasting and Diabetes
Intermittent fasting with diabetes is not simply a matter of willpower or preference — for some people it is a medication question, and getting it wrong causes hypoglycemia, a blood sugar low.
Clinical guidance on fasting sorts diabetes medicines by how likely they are to cause a low while you are not eating.
| Risk | Medicines |
|---|---|
| High | Sulfonylureas (glimepiride, glipizide, glibenclamide); insulin |
| Moderate | Meglitinides (repaglinide, nateglinide) |
| Low | Metformin; DPP-4 inhibitors; SGLT-2 inhibitors; GLP-1 receptor agonists |
Where doses need changing, the published guidance is specific: a sulfonylurea dose is skipped entirely on a 24-hour fast and halved for a partial-day fast; basal insulin is reduced by a third to a half depending on control; and mealtime insulin is skipped for a meal with no carbohydrate in it. Anyone fasting on insulin or a sulfonylurea may need to check their glucose as often as every two hours.
The same guidance discourages fasting altogether during pregnancy and breastfeeding, in young children and frail older adults, and in anyone with a history of an eating disorder.