He had more than weight gain, he suffered serious liver problems. That was in the movie despite him hiding his chronic alcohol abuse. Eating tons of fast food i

He had more than weight gain, he suffered serious liver problems. That was in the movie despite him hiding his chronic alcohol abuse. Eating tons of fast food is obviously going to be unhealthy, but the results are pretty predictable. There's a scene at the outset where a doctor tells him something like "you'll gain weight and raise your cholesterol but that's about it" and he came back with loads more problems. The extra problems were most likely due to alcohol.