Glycemic index (GL) can classify a carbohydrate (carb) as either good or bad. GL is an indicator of how fast your body digests carbs. The higher a GL number, the worse it is for you (in excess).
Foods high on the GL table are referred to as simple carbs. They are high in real sugar and low in fiber (because it is removed during processing). Simple carbs tend to spike blood sugar and provide very little nutrition. For those two reasons they should not be used as a primary source of nutrition.
It is O.K. to have them once in a while, but not all the time. Foods falling into the bad carb category typically include: soda, candy, artificial syrups, pastries and desserts. White rice, bread and pasta are also on the list because during processing, the fiber was processed out of it.
Even within the simple carb category, some foods are better choices than others. For example, a cup of white rice has a GL of 91, but the same serving of white spaghetti only has a GL of 64 making it a better choice.
Good carbs are referred to as complex carbohydrates. They are low in sugar and high in fiber. Usually anything made from a whole grain falls into the complex category because it hasn’t been processed, thus retaining much of its fiber. Fiber keeps you fuller longer, thus curbing your appetite longer. In the end you’ll consume fewer calories making weight management easier.
Choosing a good carb over a bad one is as simple as choosing brown rice instead of white, or a whole grain bread over one made with white flour. As far as GL value, a cup of brown rice has a value of 79 while the same measurement of white rice shows up at 91.
Most Glycemic Index tables also contain one other type of carb measurement – Glycemic Load. The GL Load of a food refers to the amount of carbohydrates in a food. The lower amount of carbs, the less impact it will have on blood sugar spiking. Some foods can be misleading if you look just at their GL Load.
For example watermelon has a high GL of 103, but a low GL Load of only 52. Compare that with another fruit the pear; it has a GL of 54, and a GL Load of 57. Watermelon has fewer carbs than a pear even though it has almost twice the GL value.
The bottom line is choose carbs sensibly. Focus on eating whole grains, fruits and vegetables to get the nutrition your body needs. Minimize eating simple carbohydrates that spike your blood sugar and make you hungry sooner.