If that means pizza, then fine, but also include some carrots or fruit (strawberries, grapes, etc.) to balance it out. If you restrict them to ONLY "healthy" foods, they will end up over eating those restricted foods later in life when they have no one to tell them otherwise.
Limit the candy and snacks to small portions, and only once or twice a day (never before lunch). Kids need protein as well as veggies, so let them have the occasional burger or whatever, just balance it with something good.
This is just my opinion. My kids are 8 and 6, so we battle with this daily as well.
My girls are small now (13 and 10 months) so I feed them baby food and milk still, but from the beginning I opted for organic baby food and now that I can give my 13 month old regular milk, I also give her organic. I've also started giving her table food, which consists of whatever we are having in small amounts. I would say that "healthy food" starts out with the ingredients you use to prepare it. Even if I am not feeding them fried foods and sweets, if I buy a lot of processed, hormone ladened and pesticide covered ingredients, in my opinion, I am still feeding them "unhealthy", so I will try, when it comes time for table food only, to do what I do now and that is to buy organic and naturally grown as much as I can. The problem us, it can get pretty expensive... Thank God for the "O Organics" brand. It is organic and natural but not as expensive as other organic labels.
Justin is nine months old...but he won't eat baby food. He loves mixed veggies (I buy the Gerber Graduates meals...and he LOVES them), mashed potatoes and gravy...chicken noodle soup....really, and mexican food....oooh that's his favorite! Guacamole and beans of any kind!