Aim: Insulin bolus doses are mainly based on ambient glucose level and planned carbohydrate (CHO) intake, although fat and protein content of food also impact glycemic excursions. We examined the impact of macronutrient intake on glycemic outcomes in youth with T1D.

Methods: Youth (N=136, ages 8-17) with T1D provided diet (3-day food records) and glucose (3-day masked CGM [iPro™]) data every 3 months for 1 year (5 time points). Diet data were analyzed using Nutrition Data System for Research (NDSR). Macronutrient % intake was derived as the mean for each 3-day period. Glycemic outcomes were A1c and CGM metrics: glucose % time in range (TIR) 70-180 mg/dL, % time (T) <70, %T>180, and glucose CV. Longitudinal mixed models assessed the effect of macronutrient intake on glycemic outcomes.

Results: Youth (48% male) had a mean age of 12.8±2.5 years and T1D duration of 5.9±3.1 years; youth checked BGs 5.6±2.4 X/day and 73% used insulin pumps. At baseline, A1c=8.1±1.0%, %TIR=49±17% (11.8 hrs), %T<70=6±8% (1.4 hrs), %T>180=44±20% (10.6 hrs), and CV=41±8%; macronutrient % intake was 48±5% CHO, 36±5% fat, and 16±2% protein. Over 1 year, differences in macronutrient intake affected glycemic outcomes (Table).

Conclusions: Our data confirm the significant impact of fat and protein intake on glycemic outcomes. These findings offer an opportunity to tailor algorithms to assist with meal-time bolus dosing and automated insulin delivery systems.


R.O. La Banca: None. L.K. Volkening: None. E. Dassau: Consultant; Self; Eli Lilly and Company. Research Support; Self; Dexcom, Inc., DreaMed Diabetes, Tandem Diabetes Care, Xeris Pharmaceuticals, Inc. Speaker’s Bureau; Self; Roche Diabetes Care. Other Relationship; Self; Dexcom, Inc., Insulet Corporation, Roche Diabetes Care. S.N. Mehta: None. L.M. Laffel: Advisory Panel; Self; Roche Diabetes Care. Consultant; Self; Boehringer Ingelheim Pharmaceuticals, Inc., ConvaTec Inc., Dexcom, Inc., Insulet Corporation, Insulogic LLC, Janssen Pharmaceuticals, Inc., Lilly Diabetes, Novo Nordisk Inc., Sanofi US.


National Institutes of Health (P30DK036836, K12DK094721)

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