The body doesn't care what is "clean". As long as it's not trans fats, eat away. Do you honestly think the sugars in a sweet potato are clean? or the sugar in corn as opposed to pure cane sugar?
cane sugar is half fructose half glucose. corn sugar is basically just glucose. cane sugar is vastly inferior to corn sugar.
fructose = no insulin, no muscle glycogen, no effect on protein metabolism, no effect on cortisol, no effect on thyroid, no effect on leptin, very easily adds to fat stores.
glucose= insulin, glycogen, stalls protien breakdown and slightly increases protien synthesis, inhibits cortisol, boosts thyroi, stimulates leptin, very difficult to add to fat stores. .
glucose carbs = good carbs. regardless of "sugar" content or glycemix load.
fructose/glucose carbs = bad carbs... regardless of sugar or glycemic load.