Ugh, I feel your pain. Ant is really hot and cold about food and he is very thin for his age/height. Now, he isn't a picky eater, he just doesn't like to eat big quantities.

He eats more when there is more food around - he is a grazer as are most kids this age. I learned this when we had a party with a big buffet. He ate more in one day than he had in previous weeks. - mainly because he controlled what he ate and when. We pushed the cookies, potato chips, etc into the middle of the table and kept the healthier options within his reach.

When I am really concerned about him eating, I'll pull out a mix of different things, put 'em on a plate and leave them on the coffee table near the TV. It will take over an hour, but generally he eats about 1/2 the food. I will also help myself too - I find if I eat something first, that increases his interest. He also likes "feeding me".

And drop the food diary if it is making you crazy. No need to make yourself crazy for no real benefit - if the increased attention from you on her eating is making her rebel (normal at this age) you are getting skewed results anyway.

Hope this helps.