Glycemic Index

All of us in the world of bodybuilding have been figuratively stuffed with information about carbohydrates. As a happenstance, we are often literally stuffed with carbohydrates.

Carbohydrates are the main source for energy and provide muscle glycogen. Of course, protein and fat can also contribute to energy and they are important for sound health and muscle growth. But 85% of your muscle glycogen should come from carbohydrates, about 60% of your caloric intake.

Bodybuilders often indiscriminately eliminate carbohydrates from their diets, since some believe that it may be the best way to drop fat and weight before a contest. The result is lethargy, poor workouts, irritability and loss of muscle mass. It is a condition known as hypoglycemia, and that is no way to win a bodybuilding contest.

What do the glycemic index numbers mean to your fat loss and muscle gains?

Insulin is released by the beta cells of the pancreas in response to sugar and amino acids in the bloodstream. Much if its importance lies in the fact that it facilitates transport of carbohydrates and amino acids into the muscle. That promotes the synthesis of muscle glycogen and protein. And that means more energy, more size, and more strength.

A problem that can arise is when too many calories are consumed (especially carbohydrates) since insulin promotes growth it also can also affect fat storage.

Insulin release stimulates the enzyme lipoprotein lipase, which plays a key role in fat synthesis. Insulin also inhibits the enzyme hormone-sensitive lipase, which encourages fat breakdown and metabolism. Insulin even stimulates the appetite.

So how do you eat enough calories to build muscle while minimizing fat storage?

Never overload your system with excess calories. That is why bodybuilders eat six smaller meals a day year round. Big meals can cause an insulin rush that tells your body to store calories as fat.

The nutrient composition of the meals is also extremely important. Your six meals should not contain excess carbohydrates because the pancreas puts out more insulin in response to sugar later in the day. This means that carbohydrates eaten later in the day have a greater chance of being converted and stored as fat than those consumed earlier in the day.

Diabetics are introduced to what is called the glycemic index. The glycemic index measures how rapidly carbohydrates are digested and absorbed. That in turn determines the effect the carbohydrates have on insulin release. The faster a carbohydrate breaks down, the more insulin is produced and the easier fat can be deposited.

Several factors influence how fast carbohydrates break down. The first is genetics, some people simply are not as affected by fast-acting carbohydrates. Their bodies secrete insulin evenly no matter if they eat beans, plums, candy or cookies. Others experience excess fat storage from high glycemic carbohydrate and a subsequent drop in blood sugar, leaving them feeling exhausted.

Other influences on the speed of carbohydrate breakdown are:

1. Ingestion time: If you shovel down 600 calories of sweet potato as opposed to eating the same amount over 15 minutes the breakdown is slower.

2. Fiber: Fiber retards the breakdown of carbohydrates by slowing glucose entry into the bloodstream. It may also increase the sensitivity of insulin receptors on the muscle so that glucose can enter the cell with ease. If the receptors are less sensitive then the pancreas must increase its output of insulin to facilitate the same level of glucose uptake into the muscle.

3. Fat and protein content: Fats and proteins delay gastric emptying, thus delaying the entry of carbohydrates into the bloodstream.

4. Chemical Structure: Choosing your carbohydrate is more complicated than simply grouping them as "simple" and "complex". Because of the structure and compositions of the foods themselves, starches break down at different rates. Look at the ratings for different potatoes for example.

Consuming lower glycemic carbohydrate indirectly promotes growth hormone output; this is by virtue of the fact that high blood sugar levels suppress growth hormone secretion. Not only is it a good idea to consume slow-acting carbohydrate during the day, it's more important at night. In adults the largest burst of growth hormone occurs during the first 90 minutes of sleep. To maximize this effect, limit your carbohydrate intake for a least three hours before bed.