When challenged with a high-fat diet (HFD), LFABP null (LFABP−/−) mice become substantially more obese compared to their wild-type (WT) counterparts, but they maintain a metabolically healthy obese (MHO) phenotype characterized by normoglycemia, normoinsulinemia, decreased hepatic steatosis and increased spontaneous physical activity [3]. The gene discussed is FABP1; the disease is fatty liver disease.