I've been in a similar situation a couple of times before, and I always make a point to apologize directly to the child for their parent's 'terrible behavior'. That usually gets the shitty parent really riled up, which is always good for a laugh.
Madness string 98197
Addiction is compulsive engagement in a thing despite consequences. Unfortunately diet tends to be a slow burn; you don't feel blood pressure or sugars creeping up until really it's too late. You can more or less live a normal life before you deal with the consequences in your late 20's.