| I like to fast for a couple days, simply because I find it helps a lot with mental clarity. However, I think you make a good point. Fasting absolutely can have downsides. The link in the comment you are replying to, for example, recommends a five day fast which is a lot longer than I've ever seen recommended. The first obvious downside is that people with health conditions like diabetes, underweight, immunocompromised, etc. need to consult a doctor first. They would probably call a 5 day fast with zero intake of food or electrolytes needlessly reckless with little evidence to support it over a shorter fast. Medical studies also tend to be of poor quality and don't stand up to meta-analysis by organizations like Cochrane. For example: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD... https://www.cochrane.org/CD013496/VASC_does-limiting-times-y... The Mayo clinic also argues theres not enough high quality evidence even on intermittent fasting at this point to recommend for or against it in weight loss (where you think it would be of obvious benefit): https://healthletter.mayoclinic.com/issues/july-2020/is-inte... Speculating on in-vitro effects and microbiological mechanisms scaling to result in things like cancer prevention or life extension seems like a fools errand. People saying "oh but it's natural" are also making a naturalistic fallacy. It was also "natural" for much of human history to be infested with parasites and ravaged by disease. Natural is not necessarily good. |
I think you are committing a fallacy here too. The naturalistic appeal is not about how things were before, but in what conditions we evolved. For example, we could try to eliminate every single germ everywhere, but that would make our immune system weaker, because our immune system can adapt itself. Vaccines are a way of leveraging that knowledge about our immune systems. Same thing about light: we spent most of our evolution time following the Sun cycles, and now we see that people that work shift hours are in a worse condition than people that don't.
A big difference between the way we fast today and the way people may have faster before is that we don't have to hunt or gather for our food, we have certainty about the presence of food at the end of a fast. Though by writing that, I wonder if early humans felt constantly the need for food and the fear of not finding it. I don't even know if animals do.