Each subject will be studied twice 4-6 weeks apart in random order in this single blinded study. In study A they will receive a single dose of insulin 40 IU through nasal spray. In study B they will receive placebo. On the day of the study subjects will drink regular liquid nutrient formula to maintain a constant fed state. A pancreatic clamp (octreotide with replacement glucose, insulin and growth hormone) will be started at 7am. From 9am a regular infusion of a stable isotope tracer will be started together with nasal spray of either insulin/placebo. Regular blood samples will be drawn to assess lipoprotein kinetics.