IIRC, he was only kinda under medical supervision. He, more or less, called some doctors and said he was going to do it, I'm sure they thought he was crazy and lying but they agreed to do fairly regular check-ups anyway. He met with them every month or so; probably more often at first. They gave him potassium supplements for the first few months, but nothing after that. We don't know if he truely ate nothing; he could easily fit in liquid calories or small snacks, but he ate close enough to nothing that we could call it a starvation diet. I think he stopped when he was still in the overweight range; I couldn't find records of if he continued weight loss at a more sensible pace afterwards. After 200 pounds of lost weight over about a year, the body needs some time to adjust and shrink everything down to human sizes.