I need help!

DD is 4 and a bit and is SO skinny. She hasn't put on any weight in 2 years and was only a bit chubby back then, so now there's nothing to her but she's quite tall and when she's undressed you can see her ribs front and back.

She eats 2 weetbix for breakfast most mornings, but after that it's anybody's guess how she'll go each day. I know she does eat recess and lunch 2 days a week at kindy, because she comes home with an empty lunchbox and all the wrappers are still in the box. If she doesn't eat something it stays in her lunchbox. Daycare says she eats there but I'm not sure. I know she eats when she stays at my dad's on Thursdays because he won't let her get away with not eating. When she's home sometimes she'll eat constantly, other times she won't eat more than 2 mouthfuls. Dinner is pretty much a write off unless its a sandwich.

I've tried everything to get her to eat - serving her favourite foods, eating at the table, in front of the tv, sitting with her, leaving her alone, getting someone else (not DH or I) to sit with her, feeding her, giving her snacks rather than meals, not letting her eat between meals, helping to prepare her dinner, telling her if she didn't eat she'd get sick (I was desperate - didn't work anyway ) I just don't know what to do anymore. She hasn't LOST any weight thank God, but she can't keep this up, especially at the rate she's growing taller.

I don't think it would be a gastric issue because some days she eats and eats and eats, and she doesn't complain of stomach pains or anything when she does eat, she still goes to the toilet normally and has normal bowel motions.

If anyone has any suggestions it would be greatly appreciated - I really don't know what to do short of taking her to the doc.

HELP!

Bel