There are many things around Agon that you can eat. Many of the things you find off of mobs or from harvesting nodes can be eaten as is or saved and turned into higher tier food. For example, while harvest, you will undoubtedly find berries of different types. You could eat them as is for a small buff or save them to cook into something greater for a much larger buff.
All characters in Rise of Agon will want to carry food on them so the cooking skill is very valuable. You can craft slowly from your bank or faster from the related crafting table.
Consult this crafting Google Doc and flip to the relevant tab for the various items you can make and what you'll need.