They would have had to rely
> on accumulated folk-knowledge, folk wisdom, myths, religion, cultural
> rules etc. as well as practical availability and personal preferences to
> make their food choices.

alos the most important animals and humans developped and rely on an
instinct to regulate their food intact via their sense of taste and smell .
those senses don't perceive odors and texture in a fixed way but in
relationship with their metabolic state .

this article below show in a very crude way  that smells are perceived
differently before and after a meal and the experience of instinctive eating
show us that the quality of smell is changing in a very subtle manner giving
very precises informations about the edibility or not of the moment .even
known toxin rich foods can become very pleasant to the smell and taste at
times .
jean-claude

<Abstract
Food-related and nonfood-related olfactory stimuli were presented to human
subjects before and after they ate a meal. The subjects were asked to judge
the pleasantness or the unpleasantness of the stimuli using a category
scale. The responses of ten control subjects, who remained fasted, did not
change during a 120 min period. With the other subjects on ad lib meals
there followed these two characteristic phenomena: (1) there was a
significant drop in the pleasantness of the food-related odors (negative
alliesthesia); and, (2) there was no change in the pleasantness of the
non-food-related odors (no alliesthesia). Therefore negative alliesthesia is
specific to food-related odors. Negative alliesthesia reached a maximum
within 60 min after the meals, then decreased and disappeared within the
next 60 min. In three other subjects, with abnormal body weight, negative
alliesthesia did not occur after the meal. These results favor the view that
olfactory alliesthesia plays a role in satiety and the control of intermeal
interval. They are also compatible with the existence of a ponderostat.

Mots-clé: Food intake; Olfaction; Pleasure; Alliesthesia;
PonderostatMots-clé: Prise alimentaire; Olfaction; Plaisir; Alliesthésie;
Pondérostat


*1 Travail réalisé avec l'aide de l'Institut National de la Santé et de la
Recherche Médicale (I.N.S.E.R.M.)


http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T0P-484MGJ3-BX&_coverDate=06%2F30%2F1973&_alid=215533234&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=4868&_sort=d&view=c&_acct=C000032458&_version=1&_urlVersion=0&_userid=1697204&md5=d819ac85abdc4fadb50b87561e595f10