How did people discover what is food and what is poisonous?

When I follow my parents to the supermarket, I see all sorts of food items that we eat at home, from meats to cereal to fruits and vegetables. I always wondered how people actually discovered which food items were edible, especially vegetables, since they look a lot like the plants I see around me. Did they actually eat everything they saw then realised that some items made them sick?

I’ve asked several adults this question (including my parents) and this is what they told me:

1. People saw what animals eat

   This is the easiest thing to do. Apparently people observed what animals avoided and what they ate. Giving them a clue on which items were avoided by every creature and those that were eaten by most. Makes sense, since there are so many fruits and vegetables all around us.

   
   

2. Use your senses

   If the object smells bad, then it is a natural warning sign that maybe its not for us humans.

   
   

3. Compare it to other things you know can be eaten

   The next most common sense thing to do is decide if it looks like something you actually ate before. While this can be dangerous, it helps people quickly come to the conclusion if the item in front of them is a variant of something they can eat.

   
   

4. There is an edibility test you can do

   My dad tells me that he was taught an edibility test in the army where you first take an item you think can be eaten and you rub it on your skin. If there is no rash after a period of time you then proceed to step two, which is rubbing it around your mouth near your lips. If you don’t react badly to it, you then take a small bite of the item and wait. If that works then you are almost sure! You can take a bigger bite.

   
   

5. Tastebuds as the final test

   Our taste buds usually will warn us if something is dangerous - either it is bitter or has a bad feel in our mouths (although I think a good tasting vegetable is rare).

Still, I’d recommend that we just ask the adults around us before eating anything suspicious.