At 75, I have been trying to be a fruitarian for the last 40 years. I am still trying. During nine years, 1974 to 1983, I was able to maintain a 100% strict raw vegan diet - but not for longer.

My most recent attempt started two months ago today, and is still going strong: I am doing 100% strict LFRV, based mostly on fruit, with little in the way of greens so far.
I have accumulated a lot of experience over the years, both of my own efforts and those of others, so maybe I have some useful ideas to offer.

The first thing I have learnt is that people differ very greatly in their ability to adjust to a natural diet, not only psychologically, but even physiologically. I myself am poor in this ability! Let's face the fact, very few of us are going to succeed in going all the way permanently in this. But that really does not matter at all. Let each and every one of us continue to strive to eat naturally, as far as we reasonably can.

Most people start with completely unreasonable expectations of how long this process of adaptation is going to take. Unless you have never eaten meat or fish, you will in all probability not get very far during the first TEN YEARS of TOTAL (without any binges or lapses) ABSTINENCE FROM MEAT AND FISH.
In my own case, what I could do was limited to nine years, doomed from the start in all probability because I had only been vegetarian for 3 years. Of course you may be one of the "naturals" who do not need to take so long, but more probably you will not!

So prepare for this scenario: for 5 years, you are still struggling to become a vegetarian. (Not everybody can expect to just do this cold turkey once and for all!). After 5 years, you should be able to do your 10 years of TOTAL, 100% vegetarian: no meat or fish, but eggs, dairy etc still allowed.

So you have taken 15 years so far. Now you have rebuilt your entire body, every cell in it, of material free from the rottenness and extreme toxicity of before. In the last 5 years you should also have given up root vegetables such as potatoes, onions, carrots, beetroot, etc.

Next, you may safely and easily become vegan by giving up animal produce such as eggs and dairy. Only one thing remains: to reduce your intake of cereals to nil, and to give up all other cooked food as well. Do this gradually, at a rate which you find comfortable. If this takes you another 5 years, fine.

And finally, in your own time, you emerge as a 100% natural eater. LFRV, or fruitarian.