You wanna know what ruined my night's sleep? I'm going to tell you!
So, of late I've gotten to reading Xianxia novels, and I've been a fan of the idea of ascending through sheer effort for a long time. Also, stories about gods and immortals have always been intriguing.
I've also been doing some research on nutrition and longevity, of late, running into the legend of Li Ching-Yuen. Add to this the various revelations about the dangers of gluten and whatnot, and what came to mind was, as follows:
Someone goes to hermitage on a forested mountain top. What do they eat?
They wouldn't have access to grains, and they'd likely scavenge. So they'd live on a diet of mushrooms, roots, berries, herbs, as well as hunted meat. Basically, a diet consisting of superfoods, adaptogens and such.
In addition, they'd be in a rather cold environment, meaning they'd have a lot of brown adipose tissue, participating in altutuide training, and if they happen on a hot spring ( a favourite of your wandering martial artist training on the mountains ) they might also gain the benefits of hyperthermia, such as increased HGH and EPO.
Not to mention, that come spring, they'd be getting access to a seasonal testosterone dosing - pine pollen is basically testosterone - effectively having nature's own hormone replacement therapy, which would benefit them greatly after passing sixty. It may not be a coincidence that the white pine is a symbol of longevity in China.