Animal studies have found that vitamin K-dependent proteins matrix Gla protein and osteocalcin beneficially influence lipid and glucose metabolism, respectively. However, this concept has not been tested in humans at risk for dyslipidemia and diabetes risk. Vitamin K supplementation presents an opportunity to test the hypothesized link between the vitamin K-dependent proteins and markers of lipid and glucose metabolism. The investigators will conduct an 8-week vitamin K intervention (to manipulate carboxylation of matrix Gla protein and osteocalcin) and determine its effects on markers of dyslipidemia and diabetes risk. Sixty obese children will be randomly allocated to either the control group receiving placebo or the low-dose (45 mcg/d) or high-dose group (90 mcg/d) receiving vitamin K (menaquinone-7).