Reading between the lines, it is into the territory of the New Age-y "Wellness" industry, albeit a substantial way from the insanity of sticking jade eggs up one's cunny a la Goop. Excessive belief in vitamins and hostility to conventional medication, overreliance on diet, etc. One might note for instance Steve Jobs, who potentially died because he thought to combat his cancer with herbal bullshit rather than medicine. It is a remarkable thing to consider: such a lauded man for his successes, so smart and talented, so associated with technology and progress... why oh why would he not take his meds?
I've seen psychologists suggest that some of this represents fear of illness / death, and having control. We definitely can prolong our lives and reduce risk with good diet, exercise, etc. But for some it goes too far. Life is shockingly fragile, brief, and uncertain. We really might be hit by a bus tomorrow, the volcano next our town explodes, or we get untreatable cancer, or that heart defect we didn't realise we had suddenly goes pop. The suffering of illness and death are scary. If a person convinces themself that they can control their health and the point they die, this helps manage their fear of illness and death. Then, the attraction of nature: because the idea is that we function in nature, and drugs, vaccines, etc. are both foreign to our bodies' intended experience and under the power of the medical and pharmaceutical establishment, who are very much not under our control. This is how outsize fears of adverse side effects and - at the extreme end - Bill Gates's microchips emerge: this suspicion and fear of loss of control. A major aspect is that modern medicine is very poorly understood by the vast majority using it, and that gap of understanding can be filled with fear and suspicion. Lack of understanding (thus lack of control) can also be managed, however, with pseudoscience. If it looks sciencey enough and says the things they want to hear, they can pretend they know and are in control.
It is then irony that some of unfortunates hasten their own deaths, because the psychological comfort from feeling that they are in control exceeds doing the right thing for their own health.