Thanks all.
My diet cannot be modified at all, so taking a little is out of the question. I understand how extreme it is for hosts. Which makes me a tad nervous because even if they do seem to get it, I've had two different situations now where I saw something that made me question what was in it/how it was prepared and came to find out, nope I can't eat that! I also feel bad questioning but I didn't know what else to do, I really cannot eat it at all.
I think I'll probably take food when hosts will let me. Since the diet is "tree bark and water" (I love that description, cattlekid and hope you don't mind me using it!) I find I have to eat a lot more often. I will probably have to decline eating invites with hosts who won't let me bring food and do something else instead with them.