In many ways, insulin and leptin are opposites. Insulin promotes fat storage. Leptin reduces fat storage. High levels of insulin should naturally act as an antagonist to leptin. However, the precise mechanisms by which insulin inhibits leptin are yet unknown. Both fasting insulin and fasting leptin levels are higher in obese people, indicating a state of both insulin and leptin resistance. The leptin response to a meal was also different. In lean people, leptin levels rose—which makes sense, as leptin is a satiety hormone. However, in obese subjects, leptin levels fell. Despite the meal, their
...more
