Re: Do you limit food intake?
I don't limit food (although we do limit junk). Dd eats like a linebacker, but she's TINY. However, there are occasions where she's finished a really big dinner and still says she's hungry...I will tell her to go play for 15 minutes or so and then come back if she still wants something. She almost never ends up needing something else to eat. I think sometimes it takes her body a little while to recognize the "full" signal.
I trust her to recognize what her body needs and, as long as she's getting lots of physical activity, eating mostly healthy foods, and at a healthy weight, I don't worry about it. If there comes a time when she's NOT at a healthy weight, we can worry about adjusting portion sizes then.
We also deal with tons of food allergies (including wheat, egg, fish, tree nuts, coconut, and a few more; dd has outgrown sesame, peanut, soy, and others). Have you tried quinoa? It's a high-protein grain. Whole grain pastas, breads, and brown rice are higher in protein than white varieties. Broccoli is fairly high protein, for a veg. We also do a lot of beans.