As I think I've mentioned before, Timothy and Tessa's biggest downfall is eating. They both are junk lovers, to the degree that I've already set rules for snacktime after school. Their mom has explained and categorized snacks into healthy, semi-healthy, and junk; both kids are so pro-junk that I think if I could manage to convince them that apples were junk, they'd eat four a day.
The way we operate, on the four days I'm there, is that they can have a junk snack one day, a healthy snack one day, and semi-healthy on the other two days. They pick the days, so that they don't feel like I'm controlling their lives (somewhat). Last Thursday, which was Tessa's junk day, she picked popcorn. I explained that popcorn was actually fairly healthy, and much better than the rest of the junk category - oreos, cheetos. Her reply was, "Well, I'll call it junk though, because I like it, and I like junk."