I just spent 2 days in Santiago for business and I ate KFC. (Not obese or even fat!) If the kfc in buenos aires is anything similar prepare to be dissappointed.... It is nothing like the kfc you know and love. It is nothing like edible food.
Imagine you are walking through an african labour camp, and you find a kfc, made out of starved and diseased chickens. That would probably be better than south american KFC.
Prepare to die of food poisoning, as i am right now, when kfc arrives in buenos aires.