According to this Reader's Digest article on AllRecipes.com
" white flour, refined sugar, and white rice. More broadly, any food made primarily of a carb that has been processed in such a way as to strip out ingredients that hinder quick and easy cooking. Why are refined carbs a problem? Easy: They digest so quickly that they cause blood sugar surges that lead to weight gain and other health troubles."
For ways to cut back on those bad carbs you can read the article here