We don't know enough, we might try, mainly for our amusement, in the hope by chance something we do works.
I don't agree with all this sun avoidance at all costs, yes, I know....research tells...bla, bla....
If sun exposure was so bad for our survival we would be nocturnal or living underground.
Without sun exposure there is very little if any vitamin D which unlikely would lead to an healthier and/or longer life.
Sun exposure triggers more than just vitamin D production, probably some of this processes are totally unknown or not well understood in their implications at best.
All that smearing sun protection creams, most of which containing harmful components, endocrine disruptors and who knows what else might they cause in long term use...are we really sure is it going to improve our health or ageing?
If one is of very pale complexion its evolution likely suggest a cautious sun exposure, not avoidance, just cautious.
If one is of darker complexion avoiding sun exposure is likely just against its epigenetic evolution and as such likely detrimental.
Common sense often leads to better choices than research, especially when research is still in its infancy.
Calories restriction might be OK but lets put it in perspective first.
Nowadays most people doesn't have to be very physically active at all in order to make a living and food is abundant all around us, that leads to generally overfed people, especially compared to their actual needs.
Leaving alone the junk food which floods most people diets it is quite obvious that in this context "calories reduction" makes quite sense, most people is just overfeed and reducing calories would likely just mean a more appropriate calories intake for the task at hand.
I don't think the best strategy for health and longevity is calories restriction, it would be better than nothing to whom doesn't consider changing its life style but still far from ideal.
I consider a better strategy to embrace a more active life style and eating appropriately, to me sounds like a more natural and logical choice but of course it is just my thought, no double blind clinical study yet.
Fasting 24 hours a week is another matter, it is a tradition we can find in most cultures, nowadays almost forgotten but very old and probably for good reasons.
Humans, like most animals, were designed by evolution to withstand periodical fasting times, we likely do better mimicking what once wasn't a choice but just a reality to face, willing or not.
Finally the good news: I do fully agree with you on one thing, yes, at 24 you are still relatively young!