gluten-free eats

If none of the other protein suggestions suit, maybe gelatin, whether sweetened & chilled dessert-style, or dissolved (optionally flavored) and drunk hot.

I'd start with the plain starches, though, adding oatmeal to chomiji's list if that's food for you. Tapioca pearls or tapioca pudding if you like those.

Wishing you a speedy recovery.