You find carbs in foods containing sugars, starch, and dietary fiber. Natural sugar from fruit (fructose) isn't as bad for you as refined, or processed table sugar (sucrose), but they can cause problems. The main problem caused by carbohydrates is increased insulin levels in the blood. When this happens on a repeated basis, your body becomes insulin resistant. Extreme levels of insulin resistance leads to diabetes type-II. Starches, like grains, pasta, potatoes, beans, and corn, can be bad for you as well due to their insulin producing affects on your body. Read more about starches HERE.
UPDATE ON STARCHES - Here's some very interesting information on starches (click HERE) that I just found this morning (10/22). Tubers: sweet potatoes, yams, potatoes, and taro, in proper quantities, can safely be eaten on a Paleo diet. The link has the info to support this. Note, however, that these foods can promote an autoimmune response and have inflammatory characteristics, because they're poisonous unless cooked. So, if you're eager to see what's going on in your gut, cut these out of your diet for a few weeks and introduce them back in slowly, and in small quantities, to see if your body reacts negatively. If, after two weeks without these, you have a negative response to eating them you'll know that you're one of those lucky people with an autoimmune response.
Bottom line: control your insulin levels by carefully controlling the intake of carbs. Balance the carb intake with protein and satiate yourself with good fats.
Learn anything new about the affect that carbs have on your body? Post to comments.