What is happening here is something else altogether. It is a psychological phenomenon that some might say resembles religion, but in any case touches on a very primeval function of our psyche. Jonathan Haidt says it's the manifestation of the "purity" value among liberals[2]. Whatever this health craze is, it is far from scientific. Even people who are otherwise very careful in interpreting scientific research, change their lifestyle based on two studies on 300 people in total, that found a decrease of 40% in the incidence of a type of cancer that affects 1 person in 2000.
In fact, heated debates over findings of such dubious nature, and a far more dubious relevance to actual day-to-day living, is a common form "religious study" among the faithful, not unlike debates in Jewish Yeshivas.
Entrepreneurs – some of them believers themselves – rush to fill the demands of this As a pseudo-scientific religion's worshippers. There is nothing wrong with that. But it should be clear that they fill a very real, and very serious, psychological need, but one that has nothing to do with actual health. As such, calling a particular magic device "bullshit" is not unlike criticizing the efficacy of a particular batch of Virgin Mary icons.
[1]: To clarify: we know how it works, but not how each of a gazilion parameters – from weather to sleeping habits to genetics to diet to exercise – affects it.
[2]: http://www.ted.com/talks/jonathan_haidt_on_the_moral_mind