I was with you until you said your kids were 1 and 3. I thought at that age, they ate what you gave them! Mine are 15 & 8. They have access to outside food on their own, so it's not so easy to make their choices for them. : )
For your ages, I've seen people recommend this site: Eat Like a Dinosaur | Paleo Parents
Eat Like a Dinosaur is their book.