Every region, every culture, had it's own idea of what 'food' is. What may be a delicacy in one part of the work is unthinkable to eat in another. Insects, eyeballs, various organs and such are all eaten in the world. It's all a matter of what is readily available in the area. Many Western cultures see such things as taboo to eat, simply because they are not as visually appealing as other dishes.
On a different note: Have you ever thought about how much of what you eat(regardless of culture) was ever considered to be food? Who was the first person to try eating something, and see if they lived? Or who first thought of how to prepare something for the first time, such as putting food in a vinegar/brine solution? Who first went "Huh, well I got this wine that went bad...some salt and other spices...wonder what will happen if I mix it all together and put this meat/vegetable in it and leave it there for a while..." I find such things interesting. It might be because I've devoted nearly a third of my life to food. Cooking it, eating it, learning about it.... Now I want to know what all of -you- think.
Initially anything that is edible, doesn't harm you, and has some nutritional value is food.
But the second level is whether the food tastes good, and is culturally accepted.
Foods and delicacies took ages to develop and evolve. Today we have complicated and specific famous recipes, these took a long time to evolve into what they are today. I don't think one day a person went out to test whether different foods would kill him. I think it went a long with evolution. Animals who tended to avoid orange cauliflower (random example lol) would live, and the cauliflower that was more brightly orange tended to not get eaten, so they co-evolved. With humans it was probably a little more different, as this knowledge was passed on by gestures and word of mouth. Then after knowing not to eat certain things, they didn't, and they made more foods as their techniques and ingredients developed and expanded. And as they formed ideas of what was clean, allowed, and good for you, they created more and more foods and recipes. Many were probably initial accidents, or random mixtures out of what they had, or what would last them through the winter.
It started with taste. When you've been eating mud, bark, and grass for a while, you will probably be pretty enthusiastic about your veggies. Then instincts made people eat salt.
I think experimenting with foods was kind of a trial and error thing. It's like how the penguins test to see if there's a predator in the water. It's "for the greater good". If George eats a strange green plant and dies, well, no one else will eat it now.
I must wonder, though... What was going through the guy's head when he decided to drink some milk?
What kind? if you mean cows milk well I have wondered similar things. I suppose we had breast milk and realised it was nice but limited in availablity. We saw that cows made more of it more of the time. And someone made the leap.
food is what you eat. people in other cultures may eat bugs while others may eat each other, it is all food. if you put it in your mouth and digest it, it is food.
