I serve the kids I watch junk but I'm okay with that. I believe everything in moderation. We go to Mcdonalds sometimes usually never in the summer and proabably at least twice a month in the winter sometimes more sometimes less. My kids and the ones I watch will also eat a bowl of salad and then ask for more. I can get them to eat pretty well I don't have any that won't eat fruit or vegetables so on a whole we eat good enough for me and the parents. I don't seem to have picky eaters though. We rarely eat prepackaged stuff as we eat gluten free/ lactose free.
What do I consider junk pretty much anything that isn't required, chips, cookies(store bought or homemade).