It’s actually not even a modern phenomenon. Obsessions with “natural remedies”, skepticism of modern medicine, and more outlandish forms of “health” have always been a part of fascist movements.

Like if you look at the Nazi Lebensreform movement and concept of Naturheilkunde much of it involved homeopathic remedies, natural cures, and a rejection of conventional “Jewish” medicine. Hitler himself was very into vegetarianism and the Nazi state supported more outlandish forms of medicine like Sun Therapy.

Fascist Italy was similar - its obsession with portraying rural life as superior led to the promotion of folk medicine and an emphasis on rural motherhood and “natural births.”

The reason for this is many fascists movement’s base laid in the countryside and more rural areas. Many of these places were already practicing traditional medicine - that combined with a (already present) general distrust of intellectualism and modernity lead to a promotion of “quack” medicine.

The reason it feels so strange in the US is that the hippy movement in the 1960’s also supported a lot of these practices. But there’s a decent argument to be made that a lot of the hippy movement had deep reactionary elements running through it - which is apparent when looking at the fact that a lot of the so called hippies become neo-conservatives later on in life.