Before agricultural and sedentary life became dominant, it is a well known fact humans were hunter-gatherers, with hunting providing the larger portion of their calories. Herbivores were plentiful and large; a single kill provided a good amount of food for a group for some time. Such a life style forced the following of herds.

Detoxify strikes me as an odd choice word. It's been the quest, and a very successful one, for farmers since the taming of the first crops to selectively improve them to obtain better and safer results at each season. There is an honorable mention with cassava, which is inherently toxic due to the presence of cyanide in the tuber, but can nonetheless be safely consumed through careful preparation.

Cooking, through the original use of fire, enabled the species to make better use of all food. Cooking facilitates digestion and the absorbtion of nutrients. Nearly all of the food consumed on the planet is cooked; unless someone is eating their food completely raw, the concer with toxicity is very low and, in my understanding, irrelevant for what we have been discussing.