I like this approach for kid's health and fitness:
5-2-1-0: A Simple Formula for Fitness
This plan is:
5 fruits and vegetables a day
2 hours max screen time
1 hour physical activity
0 sugary drinks
It's a good concept. I can nitpick it - I'd allow more screen time if you're studying (I use lots of computer-based study materials myself) and especially if you're standing or stretching while you do it. I'd want 5 servings of vegetables a day - fruit is great, but too much of it can be an issue . . . while too many vegetables is never an issue.
But overall, this is excellent stuff. It's simple, it's easy to remember, it's based on solid numbers (you hit 5 servings or you didn't, you had 0 sugary drinks or you didn't - no gray areas), and it's specific. Importantly, it is focused on behavior not results. You can always control your behavior, and that's the key.
Nice concept. You don't have to make complex plans to improve your health. Simple, quantifiable, based on actions not consequences of them.