Dietary Fat Intake Is Not Associated with Increased Insulin Resistance among Pregnant Women

Background: Dietary modification in gestational diabetes (GDM) has focused on restricting carbohydrates. Some research suggests that increased dietary fat intake, which often occurs with carbohydrate restriction, may worsen insulin resistance in women with GDM. We tested for a relationship between dietary fat intake and insulin sensitivity in pregnant women. Methods: Pregnant women in the late 2nd trimester, (median [IQR] =26 [25-27] weeks’ gestation) completed a 75 g oral glucose tolerance test (OGTT) and a validated self-administered 24-hr dietary recall. We tested for an association between fat intake the day before the OGTT and insulin sensitivity (inverse of insulin resistance, measured using Matsuda index) using linear regression, adjusting for age, race, education, parity, BMI, gestational age, carbohydrate intake, and caloric intake. We also tested for associations with insulin secretion (measured using Stumvoll 1st phase estimate, with adjustment for insulin sensitivity) , and fasting, 1-hr and 2-hr OGTT glucose (mg/dl) . Results: Pregnant women (N=120, age 34 [31-36]) consumed 82 g of fat [62-101], 235 g of carbohydrate [195-298] and 78 g of protein [61-100] during a 24-hr period. Carbohydrate and fat intake were inversely related after adjusting for total caloric intake (0.3 fewer g of carbohydrate per additional g of fat, P <0.001) . We found no association between fat intake and insulin sensitivity (β=0.07, P=0.14) . There was no association between fat intake and insulin secretion (β=2.21, P=0.62) or OGTT glucose (fasting: β=0.03, P=0.67, 1-hr: β=-0.36, P=0.26, 2-hr: β=0.01, P=0.98) . Conclusion: Our results suggest that dietary fat intake does not increase insulin resistance in pregnant women. This may have implications for dietary recommendations in women with GDM. Disclosure E.A.Rosenberg: None. E.W.Seely: None. T.Thaweethai: None. K.James: None. C.Yu: None. M.J.Callahan: None. S.Nelson: None. C.E.Powe: None. Funding National Institutes of Health (1F32DK126343-01A1) ,Nation Institutes of Health (K23DK113218) , and the Robert Wood Johnson Foundation’s Harold Amos Medical Faculty Development Program