Fridge vs Pantry

Food and I are not really very good friends. We try, but I think that deep down we just hate eachother.
I am trying to raise my girls in an environment where this is not the situation. I am trying to raise them to be responsible eaters. I am trying to offer them a well-balanced meal three times a day...
But it doesn't always happen.
My oldest is amazingly picky. She has a few foods that she will eat and refuses to budge. If there is a speck of "green stuff" (spices) on her food then you may as well throw in the towel because she won't be eating it.  She is also very skinny. Shocking, right?!?!
My middle child has always been a good eater. We skipped right over baby food. She basically went from nursing to steak! She is starting to develop more preferences; however, she is willing to try new foods and often times likes them.
My baby is a good eater; however, she has already had a lot of dietary issues that we are still working out. She can only have certain dairy products and has some other GI stuff we are working to resolve. She is entering into the 2 year old stage of not eating much. I am not worried about it since I have seen my other girls go through it.
My girls are all fairly small. They usually fall well below average for weight. Their doctor laughs and says, "Well, mom, I wouldn't expect them to be big because you are not." I suppose that is true. However, I think that because they are skinny, I worry less about what they eat. I am more willing to let them have snacks that are not good for their bodies. And I don't like it.
I don't want them to struggle with food like I have. I want to teach them early. I want them to learn what is helpful and what is not. I want them to be friends with food.
My new goal is to feed my family more from the fridge and less from the pantry. More fresh foods and less processed stuff. More yogurt and less crackers. More veggies and less chips. More cheese and less candy.