One trick I've learned is to not have pop in the house. My girlfriend hates me for it :). Honestly I couldn't have quit pop if I did have it there. At one point she would buy it for her, but somehow I found myself drinking it so we had to have a discussion; thankfully she accommodated me.

Ideally you and your family can get on the same page in terms of diet, but I imagine with kids that can be extremely challenging. It's worth it if you can do it.