Not all carbohydrates are created equal. As you might expect, more natural forms of carbs tend to be healthier and less natural forms of carbs are less healthy. For example, brown rice is better for you than white sugar, although both are primarily carbs. It’s not quite as simple as it may seem however.
What’s important is the Glycemic Index of foods, or GI. The GI describes how quickly foods are broken down and enter the bloodstream. The lower the GI of a food, the more slowly it enters your blood stream and the better it stabilizes your blood sugar. The higher the GI, the quicker it enters and leaves the blood stream, creating highs and lows. For example pure sugar enter the bloodstream quickly, giving you an energy or sugar rush, but also quickly leaves, dropping your blood sugar quickly and leaving you feeling weak and spent.
Not surprisingly, low GI carbs are the best for you. Most foods that are unprocessed or minimally processed have low GI carbs, like whole grains and vegetables. The worst carbs for you are in highly processed foods like candy bars, white bread, and white sugar. As a general rule, white carb foods are unhealthy.
Healthy carbs, those with a low GI, will give you sustained energy as they enter and leave the bloodstream slowly. Bad carbs on the other hand give you a quick energy rush and are then gone. Of course all foods are OK in moderation, including the occasional candy bar and white bread, but concentrate on good low GI carbs for best health.