Aim: To discuss type 2 diabetes mellitus (T2DM) medication changes required during the popular 5:2 intermittent energy restriction (IER) diet.
Methods: A search was conducted in MEDLINE, EMBASE, AMED, CINAHL and Cochrane library for original research articles investigating the use of very low calorie diets (VLCD) in people with T2DM. The search terms used included "VLCD" or "very low energy diet" or "very low energy restriction" or "IER" or "intermittent fasting" or "calorie restriction" or "diabetes mellitus type 2" and "type 2 diabetes". Reference lists of selected articles were also screened for relevant publications. Only research articles written in English, which also included an explanation of medication changes were included. A recent pilot trial using the 5:2 IER method, conducted by our research group, will also be summarized.
Results: A total of 8 studies were found that investigated the use of VLCD in T2DM and discussed medication management. Overall these studies indicate that the use of a VLCD for people with T2DM usually require the cessation of medication to prevent hypoglycemia. Therefore, the 5:2 IER method will also require medication changes, but as seen in our pilot trial, may not require total cessation of medication, rather a cessation on the 2 IER days only.
Conclusion: Guidelines outlined here can be used in the initial stages of a 2-d IER diet, but extensive blood glucose monitoring is still required to make the necessary individual reductions to medications in response to weight loss.
Keywords: Caloric restriction; Diabetes complication; Diabetes mellitus/therapy; Fasting; Intermittent energy restriction; Medication management; Obesity; Type 2 diabetes mellitus; Very low calorie diet.