Welcome to the club that no one should be a member of. Having raised two kids on the go, cereal bars saved my life. I like the special K with strawberries. The good thing about cereal bars is that they contain less than a bowl of cereal, milk and fruit. The important thing is to get her used to eating something-anything for breakfast then gradually decrease the things that aren't necessarily good for her and substitue the things that are.
But just like adults, even if the peditrician can come up with something, she may not comply. There is an ensure type product for kids called "pedisure". You might try that.
voni