Marrow adipocytes, are unilocular like white fat cells, however both brown and white fat cells are derived from mesenchymal stem cells. The marrow adipose tissue depot is poorly understood in terms of its physiologic function and relevance to bone health. Marrow adipose tissue expands in states of low bone density but additionally expands in the setting of obesity.[3] Marrow adipose tissue response to exercise approximates that of WAT.[3][4][5][6] Exercise reduces both adipocyte size as well as marrow adipose tissue volume, as quantified by MRI or μCT imaging of bone stained with the lipid binder osmium.