I didn't take weights--I don't have a scale, but you could see it. His skin was falling flat against his body in a triangle "tent" like shape, and his spine was more visible.
He was pretty round in the middle of his body, but by his tail it got teeny tiny and skinny, just a few days after feeding (regardless of him defecating or not).

He goes through his tank every night and knocks things over, tries to lift the lid of the tank off, etc. Would parasites cause this behavior as well? I know there are some that can in other animals, but my knowledge of snakes and the parasites that use them as a host is limited at this point.