Illness is normally the accumulated waste being expelled, most all good herbs cause this as well, your never well until the waste is removed.......
Never base simple truths by looking how others look, what a teacher does is his own business, but does not mean what he teaches is bad. In all cases simple stretching exercises are great.
The churches mostly proclaim Yoga as evil and the fatter the christian the more evil yoga looks to them, they have zero concept what meditation is, they concentrate on letting their preacher prey for them while they abuse their bodies with the hopes that the lambs blood will wash them clean.