Insulin does a lot of important things for us. It pulls glucose from the blood and fritters it away into our cells to be burned for energy or stored as glycogen. It prevents hyperglycemic toxicity to neurons, pancreatic cells, the arterial walls and the generation of excessive levels of reactive oxygen species. It even promotes muscle protein synthesis and helps augment muscular hypertrophy, especially following resistance training. Clearly, we need insulin. Obviously, we don’t want to be insulin resistant. We want to be insulin sensitive. But how do we do it? 
(This Mark's Daily Apple article was written by Mark Sisson, and is narrated by Brock Armstrong)