Importantly, we show that bone marrow transplantation from RIAD mice is sufficient to drive the development of obesity in recipient mice of various genotypes (i.e., WT, Ob/Ob and Ldlr−/− mice); and that adoptive T cell transfer from RIAD mice increase body weight in T cell-deficient mice; illustrating the strong potency of T cells to promote obesity. Here, LDLR is linked to obesity due to melanocortin 4 receptor deficiency.