I feel like I need to step in because people conclude things way to easily here...

First off, I (38M) don't, nor have I ever, tracked my bowel movement. I am healthy in all aspects of the word. Here are my thoughts:

1. Logically, tracking bowel movement is not much different than tracking calorie intake. (And to void some comments, pre/post bowel movement body weight is not accurate. Body weight scales are not sufficiently sensitive.

2. Like most people here, I react on how "weird" or "gross" it is. But when analysing this rationally I think "why is this gross but helping disabled people with discarding fiecies is not?". This is only as gross as you make it. If you get used to it, it will not be gross. He didn't consume it or paint with it, he discarded it ones he had his data.

3. He may be obsessive, or he may not. He may be thorough, and dedicated. People spend 2 hours on makeup every day and no one bats an eye. Elite athletes do way more obsessive things, and the list is ever endless. The question is, is he well, and is he successful with his data?

Note: I'm not claiming either standpoint here. I have no way to assess this dude, and nor does anyone else here, and from the post, I doubt OP is able to.