It is true that the stomach stops producing acids to a large extent whilst fasting in response to no food, but will still produce some as a method of elimination (in those who are toxic) along with bile and other fluids: this can result in nausea and vomiting in some cases. The body will use every avenue at its disposal to rid itself of effluent material.
Q. How long would a fast need to be for someone of normal or near normal weight to purify the tissues completely?
A. This depends entirely on the levels of toxemia, so a difficult question to answer; but this will also depend on the amount of rest or activity as well: the more a person rests during their fast, the more energy is diverted to cleansing and healing, but if active, that energy will be channeled/diverted into physical activity. This is why Shelton and others advocated bed-rest for their patients in order to maximize cleansing and healing.
In my own case I would say that I was mostly free of toxemia after my first fast of 25 days of complete bed-rest, and after a careful refeeding programme of about one month, undertook another fast of 30 days. The first fast was wrought with toxemic elimination and an almost unbearable experience, requiring much willpower in a life and death situation; but the second fast was completely free of the symptoms of detox except for the first few days.
I used to be a vegan yes, but have learnt much since those early days. My diet is still approx' 70% raw and 30% steam-cooked (the notion that eating raw broccoli, raw cauliflower and similar cruciferous vegetables, was not that appealing)!! but my health improved even more after including some animal products. I confine these to organic chicken, salt-free cottage cheese, Pacific-caught Wild Salmon (the least polluted apparently) and Tuna.
Meat represents about one to two percent of my overall diet, but I believe it to be a significant inclusion for overall health.
Natural Hygienists even differ amongst themselves about what constitutes the ideal diet for man. Shelton I believe made the mistake of being Lacto-vegetarian and his health suffered accordingly in his later years by developing Parkinsons disease: a known cause of which is a deficiency of DHA (fish oil) and with his overworking schedule over many decades, took its toll on his myelin sheath.
Shelton wasn't perfect, but he was most certainly THE pioneer of his generation and where we have much to thank him for