There are very many different models about human health.
Energy focused, Stress focused, Hormonal and Nutrient focused and so on.
While it is incredibly lazy on my part to use the cliché of the "truth lying in the sum"
or "average" of disparate composites, this also seems to be the most accurate account.
I constantly wonder about the extent to which repeatability in some of the studies that
power the newest fad in diet or exercise. Speaking frankly, I rely almost solely on the anecdotes(broscience) and traditions(memes)
of friends, acquaintances and I people I like over any study. Someone you can physically hold, can be held accountable.
A lab coat, excuse the French, doesn't have any proximate material stakes when they get it wrong,
at least within my individual control.
With this disclaimer in mind, onward!
Several things need to be kept in mind when trying to improve one's self physically. However, I think that the most of these is the will. Both you and I know that knowledge, alone, is not enough to make one change his habits. You can learn all the pertinent facts of a matter, true or false, but this will not make you do anything. This is like wrestling with the sky. As anti-intellectual as it sounds, the constant gathering of knowledge and self-doubt a.k.a self-reflection actually leads to inaction. These facts, secret tricks and such come and go like the evening breeze, but if you have a will that is resolute it doesn't really matter what current findings say about anything.