I have no direct experience with this, but just wanted to tell you about a friend of mine. She has a daughter who is about 8 or 9, and eats hardly anything too. But they went to my mums for a steamboat dinner (it's an asian meal) .. which is where you basically cook your own food in a boiling pot of soup in the middle of the table. So you take a bit of meat, put it in your little basket, and sit it in the soup to cook it. Kinda like a fondu where you just sit and cook bits and pieces all night. Anyway... they've never seen their DD eat so much in their lives!! She also eats more when it's taco night. Perhaps the participation of cooking or assembling her own dinner is what gets her to eat?

Anyway.. just thought I'd share that. Perhaps you could give something like that a go.

I was a fussy eater as a kid - wouldn't touch vegetables (started to when I was 20! LOL) My mum often gave up with me too. She never replaced it with junkfood, but basically let me fill up on what I -would- eat.

I hope others can give you some more suggestions.