Higher glucose concentrations following protein- and fat-rich meals - the Tuebingen Grill Study: a pilot study in adolescents with type 1 diabetes

Objective: Traditionally insulin dosage is focused on the carbohydrate amount of meals. We investigated the influence of a fat- and protein-rich meal in the evening on glucose concentration over night in adolescents with type 1 diabetes.

Research design and methods: Fifteen patients, mean age 16.8 [standard deviation (SD) 2.9] yr participated in the study. Mean glycated hemoglobin (HbA1c) was 6.9 (range: 6.0-8.9) %. On two consecutive days the patients received a standard meal (SM) and a fat-protein-rich evening meal (FPRM). The carbohydrate amount remained identical and insulin was adjusted to this carbohydrate amount with the individual carbohydrate bolus. Glucose was measured continuously over night with the Enlite sensor and the Guardian system (Medtronic) during the following 12 h after the meal.

Results: Glucose area under the curve (AUC) for SM was 1400 (SD 580) mg/dL/12 h and for FPRM 1968 (SD 394) mg/dL/12 h (p < 0.05). There was a significant difference in the AUC between 4 and 12 h after the meal. Maximal AUC difference was 6 h after the meal. Glucose concentration in the morning (12 h after the meal) differed: 91 (SD 34) mg/dL after SM and 153 (SD 60) mg/dL after FPRM (p < 0.05). For SM 31% of glucose level were <80 mg/dL and 24% >150 mg/dL, for FPRM it was 3 and 48%.

Conclusions: Twelve hours after a FPRM glucose concentration is significantly higher. Dietary counseling should include the effect of protein and fat on glucose levels in adolescents with type 1 diabetes. The data indicate clearly a need for additional insulin for fat-protein-rich meals.