Keep in mind that everyone is different. Too many variables and not enough control. Some people cheat by "adding" into their regimen and come to report that following one plan without supplematation cured them completely.
What also is not know is the health of that person. Some people have underlying conditions, often unknown to them that directly, indirectly, or accidentatly get "fixed" which then leads to them claiming it solved their acne.
I do not discredit those for who it has worked. But like i said, too many variables and unknowns
I for one was never really helped by any "diet". This includes when i was running 10k daily. I was physically in the best shape I had ever been, eatting moderately better than I had in the past without pills. I still had problems guys. Still.
Then nursing school happened. I lost my muscle mass, dropped 27lbs in 4 months. And to this day continue to eat like @#$%. I'm not impressed at times with myself. But thats school for ya. However, my skin has not reflect my terrible regression of healthly eatting.
On a side note; I had a full physical workup a month ago because I particpated in a medical procedure to save a life. Its been well over a year since I have ran, worked out, or have ate decent regularly. Go figure.