Effects of a Low-Carbohydrate-High-Protein Pre-Exercise Meal in Type 1 Diabetes—a Randomized Crossover Trial

Abstract

Context Current guidelines for exercise-related glucose management focus on reducing bolus and/or basal insulin doses and considering carbohydrate intake. Yet far less attention has been paid to the potential role of other macronutrients alongside carbohydrates on glucose dynamics around exercise. Objective To investigate the effects of a low-carbohydrate-high-protein (LCHP) compared to a high-carbohydrate-low-protein (HCLP) pre-exercise meal on the metabolic, hormonal, and physiological responses to exercise in adults with insulin pump-treated type 1 diabetes. Methods Fourteen adults with insulin pump-treated type 1 diabetes (11 females with a median [range] HbA1c of 50 [43-59] mmol/mol (6.7 [6.1-7.5] %), age of 49 [25-65] years, and BMI of 24.0 [19.3-27.1] kg/m2) completed an unblinded, two-arm, randomised, crossover study. Participants ingested isocaloric meals that were either LCHP (carbohydrate 21%, protein 52%, fat 27%) or HCLP (carbohydrate 52%, protein 21%, fat 27%) 90 min prior to undertaking 45 min of cycling at moderate intensity. Meal insulin bolus was dosed according to meal carbohydrate content but reduced by 25%. Basal insulin rates were reduced by 35% from meal ingestion to end of exercise. Results Around exercise the coefficient of variability was lower during LCHP (LCHP:14.5±5.3 vs. HCLP: 24.9±7.7%, p=0.001). Over exercise, LCHP was associated with a lesser drop (LCHP: Δ-1.49±1.89 vs. HCLP: Δ-3.78±1.95 mmol/L, p=0.001). Mean insulin concentration was 30% lower during exercise for LCHP compared to HCLP (LCHP: 25.5±11.0 vs. HCLP: 36.5±15.9 mU/L, p<0.001). Conclusions Ingesting a LCHP pre-exercise meal lowered plasma glucose variability around exercise and diminished the drop in plasma glucose over exercise.

Sensor-Based Glucose Metrics during Different Diet Compositions in Type 1 Diabetes—A Randomized One-Week Crossover Trial

“…In line with the current study, Dimosthenopoulos et al showed positive effects of one week of a high-protein diet (energy provided by carbohydrate: 20%, fat: 40%, protein 40%)), demonstrating that people spent less time in hypoglycemia and had lower glycemic variability compared with a reference diet (energy provided by carbohydrate: 50%, fat: 30% and protein 20%) [ 15 ]. Likewise, single meal studies with meals high in protein have shown lower mean postprandial glucose excursions, lower glycemic variability, and less drop in glucose during a subsequent exercise session [ 23 , 24 ]. This, together with the current study, suggest that maximizing dietary protein content within the recommended limits, i.e., 1.2–1.8 g per kilo body weight per day, might be particularly beneficial for blood glucose management in type 1 diabetes.…”