As a whole, carbohydrates are not bad for a person's health, according to WebMD. All carbohydrates can be divided into a list of good or bad sources, and the bad ones can lead to weight gain and diabetes. Good carbs contain fiber, energy and several nutrients essential to optimum health.
Bad carbs include refined flours, starches, processed foods and added sugars, notes WebMD. They are stripped of their fiber and nutritional benefits, and they are responsible for extreme blood glucose and insulin spikes. Bad carbs and a lack of adequate fiber in the diet can create a host of medical problems such as heart disease and colon cancer if continued for too long.
Good carbs are found in vegetables, fruits, legumes and whole grains. They can help to slow the release of glucose into the bloodstream, manage cholesterol levels and help a person feel full longer. It is recommended that good carbs comprise between 45 and 65 percent of a person's daily caloric intake, especially as a fiber source.
According to WebMD, men and women under the age of 50 should strive to get 38 and 25 grams of fiber each day, respectively. Over the age of 50, the daily fiber requirements drop to 30 and 21 grams.