Garlic is grown as food is as it is.It is also consumed in a culinary fashion.
Onions and leeks are also used in a similar fashion.This does not make them medicine nor does it mean they are consumed medicinally.
If one eats a high fiber diet it is unlikely that bowel transition time will be over 12 hrs.However if one is overweight and eating nuts which tend to be binding this could slow things down.Not to mention exercise and other things to enhance the flow of life.
I have no idea what beliefs you may be referring to.I will disclose that I do not believe in natural hygiene as the truth to all ills.
For the ideals of natural hygiene are lacking as far as nutritional completeness goes.