At 7 am (the investigators will refer to this time point as 0hr of the lipoprotein turnover study), the lipoprotein turnover study will begin. An iv bolus of deuterated-glycerol (d5-glycerol, 75 micromol/kg) will be administered, followed by a primed-constant infusion of deuterated leucine (L-[5,5,5-2H3]-leucine; d3-leucine, 98%, Cambridge Isotope Laboratories, Andover, MA, USA)(10 micromol/kg bolus followed by 10 micromol/kg/hr for 10 hours). Blood samples will be collected prior to and at regular time intervals for 10 hours after the iv bolus of d3-glycerol (for 13C-triglyceride palmitate enrichment to assess de novo lipogenesis) and start of the constant infusion of d3-leucine (for assessment of lipoprotein kinetics). Insulin sensitivity will be assessed by calculation of HOMA-IR.