Originally Posted by OsoDelDesierto

You might want to check out psyllium husks (one of the ingredients used in Metamucil - you can get them in health food stores, Whole Foods market, etc.) or something like Benefiber - you can mix them in water or a protein drink. A bit gritty, but definitely better than constipation. I'm not sure if they'll dehydrate you, but you'll need to drink a lot of water with them because the fiber will absorb water. Apart from that, I don't think either is particularly harsh. Good luck!