This is such a vast subject that I do not know where to begin with. However, I will try to compress all the info as much as I can within this post.
Well, man by nature is a fruit eater (frugivore) The whole human structure is adapted to eating alkaline plant-based products (the only species that is adapted to eating acidifying products are animals from the cat family). Fresh fruit and vegetables (with emphasis on fruit) are alkaline. Vegetables are "man-made", they are not entirely natural, but I don't mean that they are not ok, it's just that fruit is the best option for our species.
It is an undeniable fact that fruit is largely hybridised, grown on poor soil, treated with chemicals, picked unripe (making it acidifying rather than alkalizing) and transported vast distances. However, despite this, I believe they are still the best choice for our species.
Under ideal conditions (i.e. we live in the tropics, fruit is available all year round, preferably organic and from our own garden), we could live all the time eating only this. Unfortunately, very often, this may not be enough for us, but more on that shortly.
Introducing large amounts of protein or fat (raw or heat-processed-i.e. nuts, avocados, seeds, oils, pods and others) into a vegan diet can and most often does result in negative consequences. Protein in excess will always acidify the body and strain the kidneys. Besides, humans do not need as much protein as we are told. He also does not need complex proteins, because no matter from which source they are delivered (whether plant-based or animal), they first have to be broken down to amino acids, from which the body builds the protein it needs. A lot of energy is consumed for this (plant protein is broken down more efficiently, and animal protein much slower and harder). Fruits provide individual amino acids - so there is no need to use energy for breaking down the protein - the building blocks provided in the form of amino acids are simply already there and the body can use the energy for other processes.
Excess fat, in turn, will block the absorption of sugar into the cell. Sugar will remain in the blood for a long time and insulin problems will arise.
Returning to tropical ideal conditions - if we do not have them (we live in Poland for example) and if you have already completed your detox, it is usually best to eat fruit from the morning and during the day, and for the last meal to eat something partially cooked, based on the assumptions of a mucus-free diet. This could be performed every day, or it could be once every few days. I write it based on my experience with myself and with others.
A great complement to a fruit-based diet are the wild herbs - unmodified, with long roots that reach deeper into the ground than cultivated vegetables or fruit, growing wild in places not ploughed by man.
Learn to recognise at least a few types and add them to salads, juices or green smoothies. It is a real vitamin bomb! You can also drink them in the form of tinctures (on the basis of alcohol or glycerine, but it will work faster on alcohol), but that is more to support the detox and regeneration stage.
Remember that an improperly conducted detox (and the time after), without the proper preparation can bring more trouble than benefits. This is due to many factors such as the time needed for the body to adapt to new foods, the general condition of the body and individual organs, the situation in the lymphatic system, the attitude/intensity/goal of the detox, the time needed to recover from the cleansing and regeneration, etc.
Cleansing is usually not a one-time process. It is done several times, sometimes tens of times, giving the body a break between each process for the so called "relax" (provided that there is time and you can afford it, because in life threatening situations, most often it is necessary to act immediately).
Eating fruit is so simple as to be unbelievable. However, when embarking on this path, you need to do it carefully and be conscious.
There are many people who specialise in helping and supporting you to do the detox, not only me. Find one that resonates with you, that you feel with your whole self, without forcing yourself or feeling insecurities, and let them guide you (if you need it of course).
Follow your primal inner intuition :)
Lots of love!