The Paleo diet is based on the idea that if our ancestors didn't eat it, we shouldn't either. That means following a diet of natural, unprocessed foods and avoiding anything that has been altered or made in a factory. So anything that is grain-based, dairy-based, legume-based or processed is out. But there are plenty of delicious options to choose from including meat, fish, poultry, eggs, fruits, vegetables and healthy fats like olive oil and coconut oil.