specifically: is it harmful to eat the thin, brown skin (for lack of a better word) that surrounds the raw, white coconut meat? Once I have drained the coconut and removed the hard outer shell, I just dig in and enjoy. In order to avoid damaging the GI tract should I be cutting the brown part off and only eating whatever is white?
From the plant-defense perspective. A coconut is pretty well protected without having to invest additional energy into a toxic "wrapper". The only other animal that I know of (besides humans) that eat coconut is that insane crab.
Specifically, THIS insane crab...
Whoops, that's a burger-eating, cheapskate crab.
I meant THIS one!
And, just so you know that isn't a small tree...
The thin brown membrane is known as a pellicle. You can peel it off using a standard vegetable peeler. But if you don't mind the taste or texture, you don't need to, apparently. But I haven't studied the chemical composition of the stuff, just I see (from my google search) that certain fans of coconut don't mind eating it.