Ancestral Way of Eating Basics

Here is some basic information about the ancestral way of eating, also called the Paleolithic diet, among other things (Paleolithic means "old stone," as in "Old Stone Age"):

The ancestral way of eating is not so much a weight loss program--although that is a positive common side effect--as it is a health optimizer. It's the only diet based upon a fundamental explanatory model--biological evolution (or intelligent design, depending on your perspective). It's the only diet that humans are designed to eat and the only one designed by nature (or nature's God). Rather than a single, narrow fad-diet, it's actually a whole category of diets that includes a wide range of indigenous diets that were consumed by all of humanity for the first two and half million years of human existence. It is the original and longest-lasting human diet.

Paleo-type Foods:
-Wild/Pastured Meats and Organs, Fat depots like bone marrow and perinephric fat (aka suet and pork leaf fat), Seafood and Eggs (eggs or egg whites can be a problem for sensitive individuals)
-Vegetables (especially leafy green veggies and those which can be eaten raw; [some Paleo dieters consider sweet potatoes and white potatoes Paleo, but most still don't, though even Dr. Cordain recommends sweet potatoes for elite athletes--as always, find out what works for you])
-Fruits (optional in limited quantities, focusing on the less sugary ones like berries and avoiding or minimizing fruit juices and dried fruits; some people apparently tolerate the sugars in fruits better than others)
-Teas, Spices and most Herbs

Controversial Foods (considered Paleo or near-Paleo by some, but not others, and may be problematic for some people): nuts, seeds, heated fats (tallow, lard, etc.), honey, [processed] commercial meats, African yams, sweet potatoes, beets, sea salt (added salt may be necessary for carnivorous-style dieters, according to Jay Wortman, MD), [low-lactose and low-casein fatty raw dairy products like raw butter and some raw cheeses, legume tubers that are edible raw, such as jicama, yacon, Jerusalem Artichoke and Chinese Artichoke], alcoholic beverages (like wine, champagne, mead, hard liquor)

Don’t Eat (or strictly minimize) the Agrarian/Processed Foods:
-Grains (wheat, rye, barley, corn, etc.)
-Dairy (bovine, goat, etc., especially pasteurized milk and pasteurized yogurt that has sugar/sweetener/jam added)
-Beans (a.k.a. legumes; includes soy, peas and peanuts)
-Starchy root vegetables that require thorough cooking, like [white] potatoes and tapioca [I learned that sweet potatoes MAY be edible raw if soaked--they certainly taste good that way anyway, though I'm not recommending it and don't know how healthy it is to eat them that way]
-Yeast ([grain] vinegar, foods pickled with [grain] vinegar, alcoholic beverages, etc. [note: natural fermenting without yeast or high heating is supposed to be superior to industrial fermenting])
-Artificial & processed additives like sweeteners, colorings, flavorings, preservatives, excessive salt, etc.
-Heavily processed oils
-Other foods you are sensitive to (at least not at first)

Some resources:
-http://www.paleodiet.com - includes many links
-http://www.paleonu.com - Kurt Harris, MD
-http://www.thepaleodiet.com - Loren Cordain, PhD (leading scientist in the field of Paleolithic nutrition)
-http://listserv.icors.org/ARCHIVES/PALEOFOOD.HTML - Paleofood email list archives (Paleo and near-Paleo dieters)
-http://www.beyondveg.com - includes many articles
-http://ancestrallifestyle.blogspot.com - My blog
-www.ctds.info - Sandy Simmons' Connective Tissue Disorder site--good info on diet, supplements, and some disorders that result from consumption of modern foods
-www.ms-diet.org - The Multiple Sclerosis Resource Center, with info on Ashton Embry's Best Bet Diet (very close to the Paleo Diet)
-http://gluten-free.org/hoggan/ - Ron Hoggan's articles on gluten intolerance and other subjects
-www.cup.org/books/kiple/introduction1.htm - The Cambridge World History of Food

For pets:
-http://dogtorj.com, website of a veterinarian who successfully treats dogs with a biologically appropriate diet
-http://www.barfworld.com, Dr. Billinghurst’s Biologically Appropriate Raw Food

There are hundreds, if not thousands, of articles and studies on this and related subjects. If you have any special health issues, like diabetes or kidney dysfunction, make sure to check with your doctor to address your special needs.

Updates (Paleolithic nutrition is a new and evolving field and I incorporate new information into this summary post when warranted):

4.13.10 Divided controversial foods into a separate middle section; made fruits optional and emphasized less sugary fruits (some people seem to handle sugary fruits fine and others, like me, have difficulty handling any fruit); moved nuts and seeds into the controversial category (they contain mildly toxic compounds that plants use to discourage predation that may adversely affect some people); replaced "lean meats" with the better term "pastured meats"; added a link

[Note, 2009: it may seem strange that I didn't post a summary explanation of this diet until 2009, but the field was new and evolving, with controversies over what foods should be included, and I didn't feel it was sufficiently clear to me to post them until 2009. My views on what is Paleo have continued to evolve since as more information is provided by the field or my own experience. Maintain a healthy amount of skepticism and pay attention to what your own body tells you.

Update 6/20/11: I've moved mention of some foods up a level, such as sweet potatoes and raw fatty dairy products, because enough people do well on them to warrant it and the evidence against them is mixed, even though I don't tolerate some of them well myself]