If you are willing to experiment, tempeh is very filling. It's a soy product, generally sold in the produce section of any big grocery store. You cut it into cubes, boil/simmer about 10 minutes and then can use it either in a stir-fry, to augment chili, or crumbled and fried with an onion and some mushrooms. Serve over brown rice or another whole grain.
It has sort of a strong flavor so I would say it's definitely an acquired taste. But I really like it and it's very versatile.