Carbohydrates are any compounds in food made up of sugars, starches, celluloses and gums that serve as a major energy source in our diets. Good carbs give us the energy source we need to function on a daily basis, bad carbs are generally stored as fat in our bodies.
There are bad and good carbs, good carbs are generally not processed and contain lots of fiber in them, bad carbs are refined or processed having lots of sugars in them.