Understanding Carbs & Glycemic Index is important when trying to loss weight or improving your eating habits.
Understanding Carbs
Carbohydrates are your body's primary source of energy. As they are digested and released into the bloodstream as glucose, they signal cells in the pancreas to produce insulin, which escorts glucose into the cells, where it is metabolized into energy. According to conventional wisdom, carbohydrates are lumped into two main categories: simple and complex. Simple carbohydrates are so named because they contain only one or two simple sugars, such as sucrose or fructose. Starchy carbohydrates, comprised of long chains of sugars, are considered complex. The old school of thought figures simple carbs are bad and should only be eaten in limited quantities, while complex carbs are given carte blanche since, in theory, they have less of an impact on blood sugar levels.
Turns out, it's much more complicated than this. We now know that the effect carbohydrate foods have on blood sugar goes far beyond the old simple-complex model. Starchy complex carbohydrates such as potatoes and rice rapidly drive up blood sugar levels like "simple" carbs, while the blood sugar effects of "complex" grains are dependent on factors such as particle size. For example, whole oats behave quite differently than instant oatmeal. This is why a preferred method of evaluating carbohydrate foods based on the glycemic index (GI) has evolved.
Glycemic Index
The GI measures the degree to which carbohydrate-containing foods trigger a rise in blood sugar levels. (Proteins and fat have little effect on blood sugar.) Foods with a low GI provoke smaller, more sustained elevations and provide a nice, steady supply of glucose and energy. Foods with a high GI, however, prompt rapid blood sugar spikes, followed by equally dramatic plummets. If you've ever experienced a "food coma" a few hours after a carb-heavy meal, you now know why.