1181-P: Substituting Protein for Fat Lowers Postprandial Glycemic Response in Gestational Diabetes

Abstract

Background: Dietary guidelines in gestational diabetes mellitus (GDM) focus on carbohydrate without regard to other macronutrients. We tested the impact of fat and protein on postprandial glycemia in GDM and analyzed whether the physiology underlying GDM influenced this response. Methods: In a pilot crossover trial, participants ate two isocaloric breakfast meals with the same carbohydrate content and different protein and fat content (High protein meal: 390 kCal, 35 g protein, 9 g fat, 45 g carb, High fat meal: 411 kCal, 15 g protein, 19 g fat, 46 g carb) on subsequent days in a random order. We measured peak postprandial glucose (primary outcome) using continuous glucose monitors. We used homeostatic model assessment to determine if participants had insulin resistant (IR) or insulin deficient (ID) GDM. We used paired t-tests to test if glycemic response to the meals differed and linear regression to test if differential response to meals was influenced by having IR vs ID GDM. Results: We studied 16 women with diet-controlled GDM (median [IQR] 31 [30-33] weeks’ gestation). Mean [SD] peak glucose after the high fat meal (146 [20] mg/dl) was higher than after the high protein meal (137 [21] mg/dl) (P=0.03), but individuals varied in their differential response to the meals (range: 25 mg/dl higher after high protein meal to 35 mg/dl higher after high fat meal). Median time to peak glucose (IQR) was 72 (63-74) minutes after the high protein meal and 65 (60-73) minutes after the high fat meal (P=0.11). There was no difference in differential glycemic response to the meals in IR (n=8) vs ID (n=4) GDM (P=0.98); age (median [IQR] 36 [33-38] yrs) and BMI (median [IQR] 27 [24-30]) adjustment did not change results (P=0.82). Conclusion: On average, women with GDM have lower post prandial glucose levels after a high protein meal compared to a high fat meal with equivalent carbohydrate content. This may inform GDM dietary recommendations and motivate research on determinants of individual-level response to macronutrients. Disclosure E.A.Rosenberg: None. T.Thaweethai: None. K.James: None. E.Kelty: None. R.L.Azevedo: None. S.Nelson: None. J.L.Garry: None. E.W.Seely: None. C.E.Powe: Consultant; Mediflix, Inc., Other Relationship; Wolters Kluwer Health. Funding Robert Wood Johnson Foundation; National Institutes of Health (5F32DK12634302); Endocrine Fellows Foundation