Just a few quick points, to help:
The main problem is that the article is all over the place. Next time, try to pick a single coherent thing that you want to say, and just say that, in as few of words as possible, with as much evidence (in the form of links to either LW, or outside sources, preferably scientific) You present far too many questions in the introduction, each of which are far too vague to actually be answered or discussed in a coherent way.
The pictures add nothing. I can think of no other LW post that uses pictures like this (though I could be wrong) There are also typos, and misunderstandings of some concepts.
I would suggest reading a little bit more of the site, specifically some of the hardcore articles about decision theory, etc. Then you will have a better idea about how to write a good post. I hope that was helpful!
Up-voted for the great links at the end about diet and nutrition as related to longevity. I’ve been looking for something exactly like that (a relatively scientific overview of nutrition as related to living as long as possible) for a long time.
Thanks!