Er, I don't mean to be too harsh, but I tend to be a bit suspicious when somebody tells me to expect weight loss, and then backpedals and says that maybe an unobservable substitution of muscle for fat took place instead. I realize there are ways this could in principle be verified, if someone was willing to expend enough effort. It is nonetheless suspicious.

I'd be more suspicious of reports that exercise didn't change body composition than that it did. That's how exercise tends to work for most people. I'd be more skeptical of the initial claim for net weight loss, at least if it wasn't qualified--- that is usually not what I would expect in the short term.

I'd be more suspicious if the 'unobservable' was a little more difficult to verify.