When insulin comes up it is usually in reference to diabetes.  Understanding the function of insulin is important for anyone eating a Western Diet who wants to achieve and maintain ideal body weight, general health, or improve athletic performance.

When we exercise our muscles use stored glycogen as fuel.  We store between 300 and 400 grams of glycogen in our muscles and another

70 to 100 grams in our liver.  The glycogen in our liver burns quicker during low intensity exercise and the glycogen in our muscles burns quicker during high intensity exercise.[i]  Having to replace these stores is one of the reasons why resistance training is more effective for weight loss then traditional cardio training.

Our bodies break down carbohydrates into sugars.  These sugars are converted to glucose to be used as energy in the body.  When more glucose is available then what is needed the excess is returned to the muscles and liver to replace the depleted glycogen supplies. Glycogen is the stored form of glucose. However, excess glucose is toxic, so insulin is released to transport glucose to the liver for conversion into triglycerides that are then sent to fat cells for storage.[ii]

Because insulin release is associated with having excess energy on hand, the presence of insulin signals the fat cells to not release energy. Over time the muscles and liver receptors become desensitized to the high levels of insulin and the person becomes insulin resistant leading to a predictable chain of obesity, diabetes, heart attack, blindness, and limb amputation.[iii]

The rate at which a food raises the blood sugar and triggers an insulin response is recorded in the glycemic index.[iv]  Fiber helps regulate the rate of digestion and therefore blood-sugar, so foods with higher fiber […]