A Low-carbohydrate Protein-rich Bedtime Snack to Control Fasting and Nocturnal Glucose in Type 2 Diabetes: A Randomized Trial

Purpose: To determine whether a low-carbohydrate protein-rich bedtime snack (Egg) could reduce fasting plasma glucose levels in people with type 2 diabetes when compared to a high-carbohydrate protein-rich bedtime snack (Yogurt) or a No Bedtime Snack condition. Secondary outcomes included glucose control assessed by continuous glucose monitoring (CGM) and fasting insulin sensitivity markers.

Methods: Using a randomized crossover design, participants with type 2 diabetes (N = 15) completed three separate isocaloric conditions: i) Egg, ii) Yogurt, and iii) No Bedtime Snack, each lasting three days. CGM was collected throughout and duplicate fasting blood samples were obtained on the morning of day 4 in each condition.

Results: Fasting plasma glucose (P = 0.04, d = 0.68), insulin (P = 0.04, d = 0.45), and nocturnal glucose (P = 0.02, d = 0.94) were significantly lower, and quantitative insulin sensitivity check index (QUICKI; P = 0.003) was improved, in the Egg compared to the Yogurt bedtime snack. There were no significant differences between either bedtime snack and No Bedtime Snack.

Conclusion: In the short-term, a low-carbohydrate bedtime snack (Egg) lowered fasting glucose and improved markers of insulin sensitivity when compared to a high-carbohydrate protein-matched bedtime snack (Yogurt). However, consuming a low- or high-carbohydrate bedtime snack did not appear to lower fasting glucose compared to consuming an isocaloric diet with no bedtime snack. CLINICAL TRIAL REGISTRY: clinicaltrials.gov (NCT03207269).