Insulin is a hormone produced by cells in your pancreas called beta cells. Their job is to keep glucose from building up in your blood, i.e., diabetes. When you eat a carbohydrate, your blood glucose level rises, your beta cells sense how much it goes up and secrete however much insulin is needed to bring it down. Insulin lowers blood sugar by opening gates on cell membranes that allow glucose to pass out of the blood and into cells.
Insulin is a powerful hormone. Too much insulin given as medication can drive your blood sugar down to dangerously low levels within minutes. Too much insulin can even kill you.
To understand why so many of us produce too much insulin, it is important to know the difference between type 1, so-called juvenile diabetes and type 2, so called adult onset diabetes. Type 1 diabetes is caused by an autoimmune reaction that damages your beta cells so you produce less than normal amounts of insulin. In type 2 diabetes you produce plenty of insulin. The problem is that your body loses responsiveness to insulin so you have to produce more than normal amounts of insulin to control your blood sugar. Years of insulin overproduction causes the beta cells to virtually wear out from overuse. When they can no longer keep up with demand, your blood sugar rises–you become diabetic.
Insulin Resistance
The main consumers of glucose and the target of most of the insulin you produce are your muscles. They burn glucose and fat to do their work. But muscle cells can only hold a limited amount of glucose. So when your muscles have all the glucose they need they, they stop responding to insulin—they become “insulin resistant.”
What happens to the glucose in your blood when your muscles are insulin resistant? There’s one kind of cell that never stops responding to insulin, and that’s your adipocytes, otherwise known as “fat cells.” When your muscles shut their doors to insulin, glucose levels in your blood rise, which causes your beta cells to secrete more insulin. High insulin levels drive glucose into your adipocytes, which convert it to fat.
Think about it: insulin turns glucose, which you get from eating all carbohydrates including fruit and veggies, to fat. In fact, when it comes to pushing calories into your fat cells, insulin doesn’t discriminate. It converts fuel from all three sources of calories—carbohydrates, fat and protein–into fat.
