Image: Derek Dysart via Creative Commons
That image of a caveman gnawing on a hunk of bison meat may need a makeover. A new chemical analysis of modern diets suggests Stone Age humans ate less meat than thought.
The findings, published in the November issue of the American Journal of Physical Anthropology, may explain why many archaeologists estimate that prehistoric people got most of their calories from lean meat or fish when modern humans would be literally poisoned by such a protein-heavy diet.
"When you look at estimates of people's diets in early archaeological interpretations, it's very animal-protein heavy, and that's very hard to explain physiologically," said study author Tamsin O'Connell, a University of Cambridge researcher. "We are suggesting that animal proteins were less important overall."
Diet sleuths
To see how much meat ancient people ate, archaeologists rely on the fact that protein is the only macronutrient that contains nitrogen. Different foods have different ratios of heavy and light nitrogen isotopes, or atoms of the same element with a different number of neutrons. So in a given ecosystem, scientists can reconstruct ancient diets by measuring the fraction of heavy-to-light nitrogen isotopes in fossilized bones.
But the body also preferentially stores heavier isotopes of nitrogen, so scientists calculate an offset to adjust for that tendency when determining what a person actually ate. Historically, the offset was derived from studies in which animals were fed diets with different protein amounts. [7 Perfect Survival Foods]
Using that offset, many studies estimate that between 60 and 80 percent of the prehistoric human diet came from proteins, with most of that from animal sources.
That was surprising because no more than 45 percent of modern diets come from protein of any type.
"Even if you look at polar, Arctic dwellers, they have a lot of protein, but they have even more fat," she said. Anything greater introduces toxic amounts of nitrogen into the body.
Balanced eaters
That contradiction led O'Connell to wonder if the offset was wrong because it relied on animal estimates, not humans.
To find out, her team took human blood samples from a study where scientists meticulously re-created people's usual diets, measured exactly how much they ate over a week, and took precise samples of each meal. By comparing the nitrogen isotope ratios in the food and human blood samples, they were able to estimate how much heavy nitrogen the human body stores. (They then extrapolated their estimate for blood samples to human hair and to bone.)
Previous estimates based on animal studies were too small and thus inflated how much animal protein our ancient ancestors ate, she said.
Instead, the first farmers, who lived around 12,000 years ago, likely ate no more than 40 to 50 percent of their protein from animal sources. Those people ate a diet more similar to subsistence farmers in modern-day India or China, O'Connell said. Hunter-gatherers from the Paleolithic period also ate less meat, she added.
"We are suggesting that animal proteins would be less important overall and that's particularly true for interpretations of Neolithic farmers," she said. "What that would mean is that they are having more of a balance of animal and plant proteins in their diet, suggestive of a mixed existence strategy.”
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10 Comments
Add CommentWhy on earth do they assume that prehistoric people only ate the lean meat off the animals? Why not the nutrient-dense, fatty organ meats? Only recently in time have we started considering the organ meats as less appetizing. What do the lions eat first on a kill? Viscera. When they are done with that they go for the muscle. Therefore they would have had a diet high in fat, then animal protein, plant carbohydrate and plant protein in lesser amounts.
Reply | Report Abuse | Link to thisFirst this is a study about the very early NEO-lithic man and you are using that to extrapolate the wide variety of diets of the PALEO-lithic man(whose diet encompassed every climate on the planet).
Reply | Report Abuse | Link to thisSo there you go, this is a blatant lie of a headline to discredit actual scientific research on the proper nutrition for the human body.
The "paleo" diet is based exclusively on metabolism and has absolutely NOTHING to do with history.
You make a huge assumption that Paleo diet is mostly about meat, that Paleo subscribers just sit around and gnaw on bison meat. In fact, Paleo diet is about eating heathy vegetables, fruit, nuts, with fish, fowl, and meat--a balanced diet of real food.
Reply | Report Abuse | Link to thisMaybe, some men?, dream of a meat diet, but looking at present day hunter-gatherers, meat may be only 1/3 of the calories, 2/3 are from plants.
Reply | Report Abuse | Link to thishttp://ajcn.nutrition.org/content/71/3/665.long
Ages ago, I read that women gathered 70% of the food, men (the great hunters) supplied only 30%. Some of the food women gathered was meat, of course, worms, snails, grubs, etc, maybe the occasional mouse/rat.
But I doubt, whether "worms, snails, grubs, etc, maybe the occasional mouse/rat" is part of the modern paleolithic male diet.
On the other hand, I know that if I go to a restaurant with my wife, I order for both of us, one steak, one caesar sald, the waiter will usually, without asking, serve me the steak!
You are spot on and this is an almost painful oversite on the part of the author. Macronutrient estimates put protein at 30-35% (mainly from animal sources) but 50-60% of CALORIES from animal sources.
Reply | Report Abuse | Link to thisYes, I believe early humans had a diet similar to chimps and gorillas, which is mostly vegetarian. By the way, I am agnostic, but I read that Jesus was a vegetarian, although he may have eaten fish. Also, there have been many studies that show that diets high in fruits and veggies, and low in meats are associated with longevity. And, the raising of cows, pigs, and chickens for meat causes a great deal of greenhouse gasses. So, reducing the amount of meat you eat is not only good for your health, it is also good for the environment.
Reply | Report Abuse | Link to thisThe hunter gathers life was a harsh one.While many studies suggest that men were the greatest providers of meat.Nothing could be farther from the truth.The fact of the matter was that while women were gathering they were killing large amounts of small game.From rabbits,fish,squirrel,and fowl of all kind.Don't get me wrong the big game that men hunted was important but not for the meat,it was for the other things such as fat and skins,something not provided by small game and plants.It was this partnership between men and women that assured the survival of our species.
Reply | Report Abuse | Link to thisMen: the original Home Ec types.
Reply | Report Abuse | Link to thisWe humans must be the only creatures in the animal kingdom to have evolved into eating a 'sexist' diet, depending on whether we are male or female!
Reply | Report Abuse | Link to thisBut it's a rather risky overhang of 'nurture' over nature , for males eschewing salads as women's chow will be invariably be lacking essential nutrients coming exclusively from raw plant food; vitamin C has to be eaten by all primates on a daily basis to prevent nutritional deficiencies. Neanderthal Man ( and Woman, too) might easily have been wiped out by a sudden spell of arctic weather in which no vitamin-C giving plants could be eaten.
For a new perspective of how we are still getting primed for our food intake by original colour cues derived from plant food, you can download the free e book
Colorific Manifesto, or: Colour Eating on Youthevity.com
Thanks for sharing this diet secret....
Reply | Report Abuse | Link to thishttp://paleocavemandietfood.com