Using metabolomics, Wang et al. have identified 2-aminoadipic acid (2-AAA) as a new metabolite biomarker of diabetes risk. This nested case–control study included 188 individuals who developed diabetes mellitus and 188 propensity-matched controls selected from 2,422 normoglycaemic participants followed up for 12 years in the Framingham Heart Study. The investigators found that individuals with 2-AAA concentrations in the top quartile had a greater than fourfold risk of developing diabetes mellitus. Levels of the metabolite were increased up to 12 years before the onset of overt disease.