Theories and real scientific research will through up newer and newer facts and information generally and mostly for the benefit of human beings as a whole.
However, in most regions most of the traditional and regionally available food either raw or processed are time tested.
Finally taste and temptation dominate till alarm bells ring and force one to change to nutritious and healthy stuff.
Most foods unsuitable or toxic for our body and climate send signals through our body itself through cough, constipation, indigestion, nausea, carminative uneasiness , allergies, rashes etc if we choose to observe.
But for some people even the most toxic food does not harm and for others even the least harmful food causes problems.
Ironically, we all realise very late in life that food is one area where moderation is the vital aspect.