Although Dgat1−/− and iDgat1−/− mice are resistant to diet-induced obesity, the absence of a comparable phenotype in Dgat1−/−ApoE−/− [11] and iDgat1−/−ApoE−/− mice upon WTD feeding is likely the consequence of the resistance to diet-induced obesity caused by ApoE deficiency [23]. Here, APOE is linked to obesity due to melanocortin 4 receptor deficiency.