Improvement in insulin resistance after gastric bypass surgery is correlated with a decline in plasma 2-hydroxybutyric acid.

•This is the first report of a decline in 2-hydroxybutyric acid in response to bariatric surgery. Correlation between insulin resistance and 2-hydroxybutyric acid suggests the utility of the latter as an excellent biomarker for tracking glycemic improvement, and offers further insight into the pathways that control diabetes.