I can't speak for your adolescents, but my kids make generally good decisions. I don't relate to the kids are stupid automatons with no agency or valid opinion mindset that is so prevalent with HN contributors. If your kids would only ever pick junk food, maybe that is a reflection on you more than them?

I myself was recently an adolescent, and still know many adolescents myself. My take is coming from my anecdotal experience, and the behaviour I've observed from my peers. Perhaps your kids don't show that side of them in front of you? I know my peers and I certainly didn't go out of our way to advertise such activities to our parents when we were younger.