First-line, conventional dietary treatment for gestational diabetes (GDM) recommends a carbohydrate-restricted, higher fat diet to reduce postprandial glucose and mitigate glucose-mediated fetal macrosomia. However, a higher fat maternal diet may worsen insulin resistance (IR), impairing glucose uptake. Emerging studies have identified potentially impactful diet-sensitive metabolites associated with GDM, such as elevated aspartate and decreased deoxycholic acid have been associated with GDM risk and may confer worse IR. We performed a targeted metabolomic analysis in a subset from the “Choosing Healthy Options in Carbohydrate Energy” (CHOICE) study which randomized GDM women to a CHOICE (60% complex carb/25% fat/15% protein) or a conventional diet (CONV, 40% carb/45% fat/15%) from diagnosis to delivery. All meals were provided, diets were eucaloric, and fiber content was similar. Plasma was collected at baseline (31 wks) and 36 wks (n=20 CHOICE; n=17 CONV) and subjected to targeted metabolomic analysis (n=527 metabolites; n=12 short chain fatty acids). Thirty-one metabolites were significantly different between diets (p< 0.05): species of ceramides (n=4), cholesterol esters (n=2), lysophosphatidyl choline (n=5), phosphatidyl choline (n=10), and triglycerides (n=6) as well as sphingomyelin C26:1, hexosylceramide d18:1/16:0, deoxycholic acid, and aspartate. Aspartate and one triglyceride species significantly decreased on CHOICE, but increased on CONV (p<0.05). The remaining 29 metabolites were increased in women on CHOICE. In contrast, CONV resulted in a slight decrease in concentration of these metabolites, and a smaller increase of the ceramide species than CHOICE. These results suggest the CHOICE diet improves metabolic markers associated with GDM and IR compared to conventional GDM diet treatments. Disclosure K.Sugino: None. T.L.Hernandez: None. L.A.Barbour: None. J.E.Friedman: None. D.Frank: None.