Had to take light eater myself, even without mutations I’ve ended up doing work to my deathmobile that leaves me parched, famished and exhausted all at once. it’s three points I’d love to put into light step and inconspicuous, but meh, not eating as much means less need to raid for food, which means you don’t really need light step or inconspicuous anyway.
Also when I had cold blooded it wasn’t that much of a problem, only a minor (circa ~5%) penalty. Maybe it’s affected by how much warmth your current clothes give? Dump those woolen socks my lizard-blooded bretheren. 
