However, unlike the above exogenous Kyn studies, depletion of Ido1 attenuated body weight gain (Fig. 1j) and improved insulin resistance induced by HFD (Fig. 1k–m and Supplementary Fig. 2d–f), while no perceptible change was noted between two groups of mice once they fed with NCD (Supplementary Fig. 2g–j). The gene discussed is IDO1; the disease is Insulin resistance.