Glucagon, rather than Glucagon-Like Peptide 1, Mediates Higher Post-Lunch Glucose Excursions during Breakfast Skipping in Asian Indian Patients with Uncontrolled Type 2 Diabetes Mellitus.

Introduction: The effect and mechanism of skipping breakfast on glycemic control in type 2 diabetes mellitus (T2DM) in Asian-Indians is unknown.

Methods: Cross-over, within-group study recruiting 5 habitual breakfast eaters (BE) and 5 habitual breakfast skippers (BS) with uncontrolled T2DM (HbA1c 7-9%). Patients underwent testing after three days of following their usual breakfast habits and after seven days of crossing over to the other arm. Fasting values and incremental area under the curve (iAUC) of post-lunch levels of glucose, insulin, C-peptide, glucagon-like peptide 1 (GLP-1), and glucagon were measured. Continuous glucose monitoring (CGM) parameters assessed were area under the curve (AUC) of post-meal glucose values, 24-hour average blood glucose (ABG), time in range (TIR), and glycemic variability.

Results: BS led to significantly higher fasting (133.5 ± 34.5 mg/dl vs 110 ± 31.50 mg/dl, = 0.009) and peak post-lunch (214.6 ± 35.07 mg/dl vs 175.4 ± 39.26 mg/dl, < 0.001) plasma glucose, and HOMA-IR (3.05 ± 3.89 vs 2.03 ± 1.76, = 0.007) as compared to BE. Post-lunch iAUC during BS was significantly higher for plasma glucose (7623 ± 2947.9 mg/dl × min vs 1922.4 ± 1902.1 mg/dl × min, < 0.001), insulin (2460 ± 1597.50 mIU/ml × mins vs 865.71 ± 1735.73 mIU/ml × mins, = 0.028), C-peptide (418.4 ± 173.4 ng/ml × mins vs 127.8 ± 117.1 ng/ml × mins, < 0.001) and glucagon (7272.7 ± 4077 pg/ml × mins vs 4568.8 ± 2074.9 pg/ml × mins, = 0.044) as compared to BE, while GLP-1 (1812.7 ± 883 pmol/l × mins during BS vs 1643 ± 910 pmol/l × mins during BE, = 0.255) did not significantly differ between the two visits. CGM revealed a higher post-lunch AUC during BS. There was no difference in post-dinner AUC, ABG, TIR, or glycemic variability.

Conclusion: Skipping breakfast led to higher post-lunch glucose excursions, possibly due to higher glucagon excursion and increased insulin resistance.