I've seen several of those in person.  One of the guys ended up losing a few toes immediately.  Another guy refused amputation of part of his foot, tried antibiotics (which we told him wouldn't work), and ended up losing his leg all the way up to his knee because he didn't listen to us.  A third fatty tried the antibiotic route, ended up in the hospital with sepsis (blood infection) and was in such bad shape that he was moved off my floor to the ICU.  Last I saw before I left that rotation, he was in a medically induced coma and they weren't expecting him to make it. Fats and feet simply don't mix.