My husband *still* has a hard time letting go of trying to get DS to eat, but he's getting there. DS often pronounces dinner 'disgusting' and says he'd rather go to bed hungry than eat it. I say ok and leave it at that. Invariably, he ends up coming back to his dinner at bed time,, because he's hungry and it's not so disgusting after all. We just leave it there for him. Sometimes, if he's had a big lunch or lots of food during the day, he's just not hungry. When we tried to get him to eat it, it became a battle and a way for him to try and control us. No fun!

Good luck!
All of that. My DD1 while tall, is quite slim. She is so not a dinner fan, unless it is toast with Vegemite. Eats well during the day but next to nothing at night. Still growing out of her clothes. Don't let it get to you. I am sure (I hope) it will pass.