Well, I just read a book by Ellyn Satter, who is a child nutritionist, amongst other things. It's called "How To Get Your Kid To Eat-- But Not Too Much." http://www.amazon.com/How-Get-Your-Kid- ... 0915950839
I was reading more for the parts on infants and toddlers, but the book covers up through the teen years. I was interested in part because obesity runs in my family, and my parents were very controlling about food, so I wanted to learn more so I could do better. I found it helpful and informative.
She promotes taking a very hands-off approach generally, when it comes to feeding kids, because kids tend to rebel against coersion even if they were planning to eat anyway. In fact, even rewarding children for making one choice rather than another (like giving a prize for choosing fruit over a cookie) will encourage most kids to rebel against the promoted choice.
She says, "It's parents' job to make the food, and bring it to the table on time. It's the kid's job to eat it."
She also says that if you don't interfere too much, children tend to be quite good at regulating what they need to eat-- so if they eat less for a while, they're still probably getting their basic nutritional needs met, and they'll probably eat more later.
Now, eating disorders are a bit different. She has a few chapters devoted to that in the book. But what you describe doesn't necessarily sound like a disorder. I think the worst thing to do would be to overreact, because that might create a disorder out of what might be just a phase.
She might be hitting puberty, and just feeling off because of crazy hormones and such.
Anyway, I hope you all figure it out. Good luck!
Oh, and Ellyn Satter also has a website, if you're interested: http://www.ellynsatter.com/physical-pro ... p-791.html
Out of the people that ever were, almost all of them are dead.
There are way more dead people, and you're all gonna die
and then you're gonna be dead for way longer than you're alive.
Like that's mostly what you're ever gonna be.
You're just dead people that didn't die yet.
The green careening planet
spins blindly in the dark
so close to annihilation.
Listen. No one listens. Meow.