Hi there-- this is a really good site. Lots of great reading on "Natural Hygiene", and the law of nature (which covers all disease and degeneration simply, if not "easily". :-))
Lots of the literature posted there is out of print.
Another good source for reading material, is "Health Research" books. They publish a lot of rare stuff--their catalogue is a nice gift in itself.
http://www.soilandhealth.org/02/0201hyglibcat/0201hyglibcat.html
Note: Before you log in, there's also a link to it at the top of this forum,(though once you are logged in, it disappears.)
Many people quote or recommend Furhman's book and 'plan' --I've only just recently scanned the book and his site--looks like a sensible rehashing/reframing/re-packaging of the old lit. but made into more of a 'program' with recipes and such for modern people who like it laid out for them, into a system. The system is "eat to live" -- it's a good idea, and OLD idea- I just prefer the older literature. strange fact; today people are told to write for a grade eight level--it might be even less; the old fasting masters and such types wrote in a way that is satisfying to the whole foods person;it's the antithesis of tweeting and all, which we seem to be awash in. (sorry, I digress)
My sense of water fasting and "nutritarian" eating as a lifestyle -it might be fuhrman who coined that word,(?) I like it a lot- is that it's really intuitive, when you get down to it, and the more you clean and prepare the temple, the clearer your own channels will be, which allows for direct knowing/download of what is "good" (high-vibration, flowing, radiant) and what is "bad" (merely segregative, low-vibration,dense and mucous-forming. . .)for YOU.
There are basic principles of course, but the fun is in the unique expression that we each are, and what best serves our highest potential. One thing's certain. We do NOT live by bread (or any food) alone. And in fact, the body needs very little, if the food is actually nutrient-dense: that gets into how to choose/find/grow nutrient-dense foods. Many people, again, go the supplement route. I like the idea of increasing the nutrients in food up to 400 percent, through culturing--that is a great way to do more with less.
For a good intro to that--the book "Wild Fermentation"
The first time I made kimchi was an ecstatic experience--(and the results were divine). I did it following along with the tutorial given by a Master (grandmother) to one Eric Armstrong. Google that, for the article.
I would not attempt/fix my mind on a 50 day wfast. Even 40n days is a big challenge for 99 percent of us--unless you feel deeply "called". (Instead, maybe think wfast and then juice and broth to total 40-plus days?) I've done 29 days on water, and wasn't in too bad a place beforehand in terms of diet -- almost vegan for years, and quite 'clean', except for daily wine.(And various grains) But I had challenges with years of toxins building up, as we all do. And what MDs usually refer to as "you're just getting older". I don't buy that, and my vision is one of getting younger. You, on the other hand, are at a great young age to build a new temple, and turn the old one into a nice garden? That is, nothing gets thrown away.
If, as you say, you feel you've really run the temple down, you may well be mineral-deficient. As Chris cautions, it's all about the reserves and where you're at when you start.
Between now and September first, I'd go all veg. and fruit, nuts and seeds, soaked, but minimal--Not gourmet vegan. Vut out coffee and all 'drinks'. Maybe scale down to two or even one meal a day.(I normally eat one meal a day, after having done a number of wfasts.) If feeling very hungry, try a "mono meal" of just all the (one) fruit you want, as much as you want. Then have another meal (after a good time of digestion) of all greens--as a smoothie, or raw soup...Lots of kale, chard, celery, . . .
that would be good preparation for say, 21 days, which would probably be a very good beginning.
Just a few coppers, to do with as you wish.
It's a great journey, happy travels. wfasting is one of the top few best ever things I've done.
Chiron