How about a quick summary for the poor guy? Here is the executive summary: Insulin acts to reduce blood sugar and store fat. You want as little insulin as necessary to do its main job of controlling blood sugar. If you are insulin sensitive, then that means you need only a very little insulin to control blood sugar, a good thing. Little insulin means little fat storage. The trouble is that overly fat people tend to be “insulin resistant” or “hyperinsulinemic” which means that when they raise their blood sugar by eating carbs, their pancreas dumps out a huge amount of insulin which drops blood sugar dramatically, resulting in tiredness and fat storage after eating carbs. (A bad thing.) It also wears out the pancreas, resulting in diabetes. The good news is that insulin sensitivity can be modified (slowly) with diet and exercise.
Now go read those articles for the full story. Mercola.com also has some good articles on insulin.