Effect of carbohydrate restriction in the first meal after an overnight fast on glycemic control in people with type 2 diabetes: a randomized trial

Abstract

People with type 2 diabetes are advised to consume an even meal distribution of carbohydrate. Whether this distribution is optimal is unknown. Objective: Our objective was to show that omitting carbohydrate in the first meal after a fast would lead to an augmented lunch response. Design: Two diets of 1-d duration that differed only in the breakfast-meal composition (carbohydrate or no carbohydrate) were consumed on sequential days in a randomized crossover study. The procedure was repeated in the alternate order 1 wk later. Blood glucose concentrations were tested with the use of continuous glucose monitoring. The primary endpoints were the percentage of time spent with a blood glucose concentration >10 mmol/L (%T >10) and peak blood glucose (Gmax). The following 45 adults with type 2 diabetes were recruited: subjects with glycated hemoglobin (HbA1c) ≤7% and subjects with HbA1c ≥8%. Twenty-eight adults completed the study. Results: The daily Gmax was significantly lower after the no-carbohydrate breakfast than after the carbohydrate breakfast (11.0 ± 0.4 and 12.1 ± 0.4 mmol/L, respectively; P = 0.003) whereas the %T >10 throughout the day was a nonsignificant 22% less after the no-carbohydrate breakfast than after the carbohydrate breakfast (13% ± 10% compared with 10% ± 8%; P = 0.09). Gmax over 5 h after breakfast was significantly lower after the no-carbohydrate meal (by 1.9 ± 0.4 mmol/L; P < 0.001), and the %T >10 was lower after the no-carbohydrate meal than after the carbohydrate meal (11% ± 3% compared with 26% ± 4%, respectively; P < 0.001). Conclusions: The withholding of carbohydrate in the first meal results in significantly decreased Gmax after the meal, but the lunch response is not affected. Overall daily control is not significantly improved.