Paleo Diet Paleo diet: why is it so popular, and what is it really? The Paleo diet is a diet plan modeled on prehistoric human nutrition. I guess it was made on the basis of the diet of the Paleolithic era, at the time when man ate at that time 2.5 million years back to 10,000 years. What does it include? It includes lean meat, fish, fruits, vegetables, nuts, seeds — food that in the distant past could be supplied by hunting and gathering. It limits the food that became commo