Systematic literature review: should a bedtime snack be used to treat hyperglycemia in type 2 diabetes?

Consuming a bedtime snack is often recommended for people with type 2 diabetes. This systematic review aims to evaluate the evidence from intervention studies to determine whether consuming a bedtime snack improves fasting hyperglycemia and/or overall glycemic control in individuals with type 2 diabetes. PubMed, Medline (EBSCO), Cochrane Library, and CINAHL Plus (EBSCO) databases were searched until 20 July, 2022. We included prospective studies in people with type 2 diabetes or prediabetes that included the intervention of a bedtime snack, consumed >30 min after dinner and <2 h before bed and reported glycemic outcomes. The systematic review included 16 studies. There was no consistent relationship between consumption of a bedtime snack and improved glycemic control, especially when a no-snack control was included. Of the 4 studies that included the use of corn starch, a low dose seemed to have benefits over high-dose corn starch in terms of improved nocturnal and fasting glucose concentrations. Current advice to consume a bedtime snack is based on a limited number of intervention studies that often do not include a no-snack control, nor have used a feasible bedtime snack option that could be translated into everyday clinical practice. Further research is needed in type 2 diabetes patients treated with or without insulin. This review was registered at the Prospective Register of Systematic Reviews (PROSPERO) as CRD42020182523.