There are some gurus and extremists out there who say you must be 100% Raw vegan or your health is damned, you're a bad person and you can expect misery for all your days. While I love Raw food and think it can solve myriad health problems, boost energy levels and simplify life, I don't tend to agree with the extremes of anything.
If you're a parent whose family eats a SAD (Standard American Diet) and you're concerned for your children, please don't fall into the trap of thinking you have to perfect their eating habits (and yours) in order to make a difference in their health, fitness, weight, or activity levels. You can make gradual changes, still rely on the occasional pizza, and improve things for your kids.
Why not start with one simple change? When your kids want a snack, they have their choice of fruits or vegetables. That's it. All you have to do is make sure there are fruits and veggies on hands, especially the ones you know they like, and discreetly dispose of the unhealthy snack foods on which they might otherwise rely. For younger children, you might also decide that, for the short term, they must ask permission before serving themselves. That way you'll be aware of what they're eating as their idea of a snack transitions from highly processed, additive heavy, boxed products, to the good stuff that God gave us to thrive on and enjoy.