We have similar problem with weight loss, similarly limited diet, no sugar, wheat, dairy, caffeine, processed foods. I try to put on weight with spelt breads, loading it up with soybutter (like peanut butter, only I'm allergic to nuts). It's very filling if you can handle spelt. I've run across spelt bread in frozen waffle form at my health food store and just toast them for breakfast. I've also found spelt in loaf and bagel form. Make sure you toast them before you eat. I've also been raiding the bulk bins at my health food store: keeping pumpkin seeds and corn nuts for snacks. My metabolism is insane, so I have to eat constantly. I hope you're not allergic to rice? That's very rare, and it's hard to replace rice as a means of gaining weight.