dnp can also cause depression while on it due to the blocking of conversion of tryptophan to seratonin - the latter being the mood controlling chemical that when low is what depression effectively is.
as for nutrasweet, there are people out there fighting against it heavily for whatever their reasons, and then they point to studies that back their ideas, and then ignore the studies against them.
I don't care if people want to have the belief one way or the other, but so far I haven't read a single study that was run even remotely correctly (double blind, proper controls, etc). and frequently you will see them citing a study, but all they really are pointing to is the hypothesis of the study - not even the results...
I haven't followed the link you showed, so I'm not trying to say that is one of those studies... just pointing out my prior observations