I believe Gerald is correct with the brain asspects of things. Most guys have no idea how to cut weight and end up skipping for hrs or sitting in a saunna for ages. Or doing something stupid and sitting in a saunna while wearing a plastic bag to help heat things up.
The day i sat in the gyms saunna with the plastic bag on there was on me and another guy in there and he was a jockey who also was wearing a plastic bag under his clothes :(