Fasting and type 2 diabetes
For patients required to fast before a medical procedure, see Periprocedural management of patients with type 2 diabetes.
Patients with type 2 diabetes may choose to fast for religious purposes (eg Ramadan) even though they are exempt from fasting. Blood glucose concentrations can be variable and unpredictable due to the contrast of fasting and feasting involved in some religious observances.
Patients who choose to fast should seek advice from their endocrinologist or multidisciplinary diabetes team. If they are at high risk of developing complications when fasting, they are advised not to fast.
Patients at moderate or low risk of developing complications may be able to fast if they are able to follow the instructions given by their clinician, such as regular blood glucose concentration checking and changes in antihyperglycaemic drug treatment if required. Practical guidelines for Ramadan fasting for patients with diabetes, including stratification of patient risk levels, have been published by the International Diabetes Federation1.