There has been no RCT which has been done in obese adolescents with vitamin D deficiency, defined as a 25(OH) D level of < 30 ng/dL (75 nmol/L) (19) and insulin resistance to assess the efficacy of using one time high dose of VD2 on indices of insulin sensitivity and secretion over a short period of time. This evidence concerns the gene INS and vitamin D deficiency.