Diet‐induced obesity (DIO) mice fed high‐dose VitD3 exacerbated markers of adiposity (body weight, fat mass, fat mass rate, size of white and brown adipocytes, mRNA, and protein levels of ATGL and Fsp27), and the protein level of ATGL and Fsp27 decreased in the low‐dose group. Here, CIDEC is linked to obesity due to melanocortin 4 receptor deficiency.