In the last few months I have been getting very active in some health forums who are investigating the cutting-edge of what is optimal health, and many members have obviously come across the Paleo diet and it's principles, and are actively practising and researching it... However after becoming a little more familiar with the underlying science, and probably more importantly an idea of the scientific investigation currently under way in metabolism and nutrition, etc, I am starting to more and more see these type of questions as not really relevant to investigating what's optimum health (but that doesn't mean it's not worth thinking about--just look at my nickname!).

The point is we know a standard Paleo-type diet is ~90% of the solution. Do this and you will mostly avoid the diseases of civilisation, which translates to a healthy old age. Now whether you go Kitavan or Inuit is totally up for debate, and potentially answers that final 10%, but looking back to 'what our ancestors did' will not give an evidence-based answer. I'm in the low-carb camp, because I have found that is what works for me, but I am left with no argument against the Okinwan's low-fat and high-carb diet producing the longest-lived people in the world. In essence I am aligning much more with Stephan Guyenet who typically espouses traditional diets over the Paleo name tag.

The Paleo diet says meat is good, fat is good, grains are bad, processed food (typically) bad, basically if we weren't eating it ~20K+ years ago, don't eat it now. It is a guiding principle. However I think it is an unfortunate truth, that if we want to know the PERFECT macronutrient breakdown for optimal health, it will have to be through some future human clinical trials, or even the newly emerging field of Nutrigenomics, i.e. we may all have different "optimal" ratios of protein/fat/carbs. My ancestors likely never consumed tomatoes, or green tea, or daily blueberries, or dark chocolate/cocoa, but modern medical science has robust evidence for the positive effects on health these compounds have, and thus I consume them. I think Art de Vany said it best "Its the fusion of the stone-age with the high-tech!"

Oh and finally, and I thought it was pretty standard knowledge that Cordain was bowing to the powers that be a little bit with his stance on SAFA, and has gradually been back-peddling for a while to the point where he will probably be endorsing it in a few years...

Another thing people ignore is the seasons. Whether it's equatorial monsoon and droughts or temperate and sub-polar summer and winter the composition of the food and the food animals changed throughout the year. After winter or a long drought the animals probably had/have an entirely different fat percentage - subcutaneously, marbled in their muscles and distributed viscerally - than they would at the end of summer or the rainy seasons. Therefore, those that prey on these animals would be eating a different diet in those seasons.

Slightly off topic, I think another thing that bothers me is that a lot of grass-fed beef proponents say that ruminants like cows don't naturally eat grain. Well, I'd be willing to bet that when the grasses they're eating are in seed those cows don't hold back. Heck, if nothing else, it helps them build up a fat reserve for winter or drought season! Even so, they surely wouldn't get the monotonous CAFO diet.

Meat is not just the megafauna. Also the small creatures. And how would those quantities relate to each other?

And a lot of people seem to ignore insects consequently when thinking about how a paleo diet originally would have looked like. Some sort of modern-day food bias... ;)

Yes, they are small, but so are nuts.

(Or am I starting a new thread here?)

The problem with your quote is this:

a) animals and plants can become extinct over time.

b) Some animals or plants evolved just like we did. People forget too often that evolution is not a human characteristic but a nature's characteristic.

c) How can we know for sure that they actually ate those animals?

d) in a similar fashion to C), how can we know which part were eaten?

Hence why most of the paleo evidence often comes from modern tribes.

The biggest animal I could find data on was polar bear...raw Alaskan polar bear meat has 26 grams of protein per 100 grams, with 3 grams of total fat and 1 gram of saturated fat. Doesn't that seem low for an arctic animal? Sometimes I suspect nutritiondata is pulling a fast one on me...

http://nutritiondata.self.com/facts/ethnic-foods/8078/2

I suspect the answer to your original question is...no. But I can see why you ask--if they kinda know what our macronutrient ratios were like, it's not that much of a leap to know what megafauna were composed of. But like others have said, we don't know what was eaten, we don't know how it evolved, etc etc.

I have seen this argument put forward before, generally refering to the animals inhabiting ice age Europe. Below are the main large mammals inhabiting Europe during the last ice age that our ancestors came in contact with (I hope I havent forgotten any):

Woolly mammoth, Cave lion, Cave bear, Cave hyena, Woolly rhinoceros and Irish elk - these all became extinct by the end of the ice age.

Brown bear, Wolf, Ibex, Chamois, Moose, Reindeer, European bison, Musk ox and Red deer - these all still exist in the wild although many in small numbers now.

Aurochs and Wild horses - these are extinct as species but continue in their domesticated forms as modern cows and horses.

In southwest France there is evidence that Neanderthals and our Cro-Magnon ancestors that replaced them hunted pretty much the same prey species.

The animals – ungulates such as reindeer, red deer, roe deer, horses and chamois were the most common prey – were the mainstay of humans in this part of the world, according to Grayson.

There is no doubt that hunting of mammoths, woolly rhino, cave bears and lions did take place, they are due to their size, less common animals. Some may have depended on mammoths but I think that for most ice age Europeans the day-to-day meat came from more common and less lethal prey animals that are still around today, particularly reindeer, aurochs and horses. Animals like reindeer and horses tend to rely on fur for insulation from the cold rather than layers of fat.

As for domestic animals, horses have always been quite lean animals as they need to run to escape predators. Domestic cattle may be smaller than the wild aurochs but I doubt that cattle were bred to be leaner.

It is my opinion that a good idea of the meat and fat composition of the diets of ice age Europeans can be worked out by studying surviving species.

Ancient animals probably had fat profiles similar to current animals. Because current animals have a variety of profiles. Some are very fatty and some much less so. Some fish are very fatty and some much less so. The fatty ones taste the best to us humans. I wonder why that is? Maybe it's cuz fat is good for us. On the flip side, I do find there is a limit to how much fat I feel like eating. I eat a certain amount and then I don't feel like eating any more. What that tells me is that my body likely knows how much is good for it and discourages me from over eating, even though it tastes so good. And that makes me suspect that my body is adapted to deal with both conditions of not enough fat, by making me like it and want more, and that it is adapted to dealing with conditions of too much fat, by kicking in satiation mechanisms.

Whereas with carbs, that satiation mechanism seems to have slowly broken down with time, such that I overeat and still am not satiated. Therefore, logic would suggest that my problem lies with the carbs. It is the only macronutrient that obviously unbalances my system.

Well, I don't have any data, but we know that as the animal gets larger, the fat percentage generally goes up. So we may be able to assume that with the larger animals, we might have been getting slightly more saturated fat than would be estimated by current animals. Then again, this is just conjecture.