Introduction: This diet really comes from a collection of research and writings about the diet of human ancestors. Although these writings are not in total agreement as to what this diet was, there are many common themes.
"Modern Paleolithic" diets are based on the idea that humans and their ancestors were evolving for millions of years before reaching the Neolithic period, during which farming and other advancements radically changed the human diet to the detriment of human health. Further changes in the last century, and even more in the last two decades, have accelerated this process.
Names: The diet goes by many different names, including: Paleo diet, Paleodiet, Paleolithic Diet, Cave Man Diet, Stone Age Diet, Neaderthin, Pre-agricultural Diet, Hunter-Gatherer Diet
Authors: A variety of authors, including Loren Cordain, S. Boyd Eaton, Ray Audette, Walter Voegtlin, and others.
Main Books: Over the years there have been quite a few books about this way of eating. The two most popular ones in print are:
- The Paleo Diet by Loren Cordain
Online Ordering: 
- Neanderthin
- by Ray Audette
Online Ordering: 
There are other books which claim to espouse an "evolutionary diet" or something similar, but don't truly go back to hunter-gatherer times. One way to tell is if the diets include grains or legumes in any great amount.
Other Writings: Those who are interested in this diet should surely check out the vast array of links on the
Paleodiet Web site.
Restricted Foods : The following foods in our modern diets were not available to Paleolithic people: any processed food, any food with
added sugars, grains except for very small amounts of whole grains, legumes, dairy products, and food additives such as artificial sweeteners. Tubers such as potatoes that require cooking aren't allowed by most of the diets.
Allowed Foods: Meat, fish, eggs, most vegetables, fruit, nuts. Some allow honey in small amounts. Some emphasize food being organic, if possible. Ideally, animals should eat a diet natural to them -- in other words, cows should eat grass, not grain, etc. Animals who eat this way have meat with less saturated fat, and is said to be healthier in other ways.
Amount of Restriction: By today's standards this diet is very restricted, as it has been estimated that close to three quarters of the standard diet in the U.S. consists of foods not available to Paleolithic people.
Amount of Structure: None - the idea is simply to "eat like a caveman", and hopefully to exercise more like him as well (which is to say "a lot"). No counting or measuring required.