Although our previous study has demonstrated that deleting apoA-IV in C57BL/6J mice exhibited comparable susceptibility to obesity as WT mice [10], the current study backcrossing apoA-IV−/− mice onto the 129/SvJ background has characterized several significant metabolic phenotypes that emphasize the effect of apoA-IV on weight control. Here, APOA4 is linked to obesity due to melanocortin 4 receptor deficiency.