During and Post Exercise Nutrition - the Role of Insulin

About five months ago, my brother gave me this book called Nutrient Timing by John Ivy and Robert Portman and I've finally got around to opening it. I'm not even 30 pages in, but I've already learned something pretty cool. Basically, insulin is your best friend and then some.

Insulin is stimulated by an increase in blood sugar. Its primary role is to tell your body to store that sugar. Normally, that storage would occur as fat, but during and directly after exercise, things are a little different.

During this time period, the muscles are especially sensitive to insulin. If you take in a whole bunch of carbohydrates during and after exercise, your muscles will suck it all up and store it as glycogen. Sound good? Well theres more.

Insulin also affects the way your muscles handle protein. High levels of insulin (which you'll recall are brought about by taking in carbohydrates) increase the rate of protein uptake by the muscle from the blood. Insulin also increases the rate of protein synthesis and decreases the rate of protein degradation. That means you'll not only bring more protein in, but you'll loose less protein (a process that, unfortunately for athletes, naturally occurs following exercise). Insulin also decreases the release of cortisol whose role is to free up glycogen, fat and amino acids. Cortisol is released during exercise to give you energy, but once you're done exercise, it will only slow recovery. Insulins inhibition of cortisol is probably the reason that protein degradation decreases.

Insulin does one more awesome thing: it increases blood flow to your muscles. Not only that, but it targets muscle that have been damaged, bringing nutrients and eliminating wastes.

Here is the take home message: make sure that you take in carbohydrates during and after exercise. This will allow your body absorb protein better, break down energy stores less and generally speed recovery. Have your protein following exercise with a healthy serving of carbohydrates and have your giant plate of pasta as soon after exercise as possible (45-90 minutes).