Insulin is a hormone secreted by the pancreas in response to elevated levels of glucose (blood sugar). Its function is to move the glucose into the body’s cells to be used for energy. Insulin is also the fat storage hormone — excess glucose that is not burned as energy or stored in the cells as glycogen will be converted into adipose tissue (fat). See the Insulin-Fat Connection by Dr Richard Bernstein.
Insulin resistance is a condition in which the body’s cells fail to respond to the normal actions of the insulin. The body produces insulin, but the cells in the body become resistant to it and are unable to use it as effectively, leading to hyperglycemia (excess blood sugar). Beta cells in the pancreas subsequently increase their production of insulin, further contributing to hyperinsulinemia (excess insulin in the blood). This often remains undetected and can result in Type 2 Diabetes.
For a good overview of insulin resistance, obesity, and Type 2 diabetes, see Dr Sarah Hallberg’s TEDx talk below, titled Reversing Type 2 diabetes starts with ignoring the guidelines.
Dr Hallberg is the Medical Director of an obesity clinic in Indiana, and she says that the American Diabetes Association’s recommendations to eat 45-60 grams of carbohydrate per meal is making patients worse — carbs raise blood sugar, and that is exactly what T2 diabetics need to avoid. As Hallberg points out, “Diabetes is a state of carbohydrate toxicity. Insulin resistance is a state of carbohydrate intolerance.”