Friday, August 1, 2008

Composition of the Hunter-Gatherer Diet

I bumped into a fascinating paper today by Dr. Loren Cordain titled "Plant-Animal Subsistence Ratios and Macronutrient Estimations in Worldwide Hunter-Gatherer Diets." Published in 2000 in the American Journal of Clinical Nutrition, the paper estimates the food sources and macronutrient intakes of historical hunter-gatherers based on data from 229 different groups. Based on the available data, these groups did not suffer from the diseases of civilization. This is typical of hunter-gatherers.

Initial data came from the massive Ethnographic Atlas by Dr. George P. Murdock, and was analyzed further by Cordain and his collaborators. Cordain is a professor at Colorado State University, and a longtime proponent of paleolithic diets for health. He has written extensively about the detrimental effects of grains and other modern foods. Here's his website.

The researchers broke food down into three categories: hunted animal foods, fished animal foods and gathered foods. "Gathered foods" are primarily plants, but include some animal foods as well:
Although in the present analysis we assumed that gathering would only include plant foods, Murdock indicated that gathering activities could also include the collection of small land fauna (insects, invertebrates, small mammals, amphibians, and reptiles); therefore, the compiled data may overestimate the relative contribution of gathered plant foods in the average hunter-gatherer diet.
There are a number of striking things about the data once you sum them up. First of all, diet composition varied widely. Many groups were almost totally carnivorous, with 46 getting over 85% of their calories from hunted foods. However, not a single group out of 229 was vegetarian or vegan. No group got less than 15% of their calories from hunted foods, and only 2 of 229 groups ate 76-85% of their calories from gathered foods (don't forget, "gathered foods" also includes small animals). On average, the hunter-gatherer groups analyzed got about 70% of their calories from hunted foods. This makes the case that meat-heavy omnivory is our preferred ecological niche. However, it also shows that we can thrive on a plant-rich diet containing modest amounts of quality animal foods.

The paper also discusses the nature of the plant foods hunter-gatherers ate. Although they ate a wide variety of plants occasionally, more typically they relied on a small number of staple foods with a high energy density. There's a table in the paper that lists the most commonly eaten plant foods. "Vegetables" are notably underrepresented. The most commonly eaten plant foods are fruit, underground storage organs (tubers, roots, corms, bulbs), nuts and other seeds. Leaves and other low-calorie plant parts were used much less frequently.

The paper also gets into the macronutrient composition of hunter-gatherer diets.  He writes that
...the most plausible... percentages of total energy from the macronutrients would be 19-35% for protein, 22-40% for carbohydrate, and 28-58% for fat.
He derives these numbers from projections based on the average composition of plant foods, and the whole-body composition of representative animal foods (includes organs, marrow, blood etc., which they typically ate). 

However, some groups may have eaten more fat than this.  Natives on the North American Pacific coast rendered fat from fish, seals, bears and whales, using it liberally in their food. Here's an excerpt from The Northwest Coast by James Swan, who spent three years living among the natives of the Washington coast in the 1850s:
About a month after my return from the treaty, a whale was washed ashore on the beach between Toke's Point and Gray's Harbor and all the Indians about the Bay went to get their share... The Indians were camped near by out of the reach of the tide, and were all very busy on my arrival securing the blubber either to carry home to their lodges or boiling it out on the spot, provided they happened to have bladders or barrels to put the oil in. Those who were trying out [rendering] the blubber cut it into strips about two inches wide, one and a half inches thick, and a foot long. These strips were then thrown into a kettle of boiling water, and as the grease tried out it was skimmed off with clam shells and thrown into a tub to cool and settle. It was then carefully skimmed off again and put into the barrels or bladders for use. After the strips of blubber have been boiled, they are hung up in the smoke to dry and are then eaten. I have tried this sort of food but must confess that, like crow meat, "I didn't hanker arter it".
I was very impressed by the paper overall. I think it presents a good, simple model for eating well: eat whole foods that are similar to those that hunter-gatherers would have eaten, including at least 20% of calories from high-quality animal sources. Organs are mandatory, vegetables may not be. Sorry, Grandma.

14 comments:

Debs said...

Thanks so much for posting this. I was getting into a lively debate in the comments section of another site, with people who thought that hunter-gatherers (or "gatherer-hunters" as they said) ate very little animal saturated fat because animals were allegedly so hard to catch and meat spoils. I posted a link to this piece.

I found an interesting chapter here (pdf) about saturated fat intake in hunter-gatherer diets. The author basically shows that we evolved eating saturated fat, and debunks the idea that we should keep saturated fat in our modern diet low. Although I was surprised that he estimated HG saturated fat intake at only about 15%. He also agrees that HG diets varied but had certain important elements in common.


Debs
Food Is Love

Stephan said...

Hi Debs,

Thanks for the link. That paper is also by Cordain, and he recycled some of the figures from the paper I discussed in my post. I think Cordain, while not falling into the typical anti-sat fat trap, still has a bit of a bias against it.

Cordain and others claim that wild animals don't have much saturated fat, but again that's based on "representative" animals that aren't so representative. One of his ideas is that wild ungulates have less saturated fat than modern beef, but that's only true during certain times of year. The fat composition (%sat) of wild ungulates is very similar to modern beef, and temperate-climate ungulates become at least as fat as modern cows in the fall. So HGs would have eaten a lot of saturated fat, at least in certain places and at certain times of year.

He also ignores data from cultures that eat a lot of saturated fat and are very healthy. Pacific islanders have been eating coconut liberally for thousands of years (92% sat), and the Masai eat arguably more saturated fat than any other population on earth. We have good, modern data for both cultures indicating that neither got heart disease or any other disease of civilization.

I do believe you can be very healthy following Cordain's advice, I just think he's a bit too restrictive. There's no way I'm going to cut the fat off my steak!

AA said...

It seems likely that many HG groups obtained fat from less savoury sources as many Australian aborigine groups were prone to do:

In NSW, many instances were recorded on the Bollon and Mooni Creek regions of “human burnings”, “meat eatings” and “collections of body fat juices”. In Victoria, there are numerous reports that the Maneroo, Brajeracks, Narrinyeri, Merkani and the Tattiara were indeed cannibals and seekers of “fat” people to eat – and to gather body fats.
link

Sorry about lowering the tone of the discussion but the mentioning of fat is interesting.

Stephan said...

Delicious.

Varangy said...

Hi Stephan,

What would you advise for organ meats? Which ones and how would you prepare them?

Thanks in advance.

Varangy said...

Whoops. Forgot to tick follow-up box.

Drs. Cynthia and David said...

Thanks for the posting Stephan. I've read some of Cordain's work, including his Paleo Diet books. Generally, I think his work is interesting and a move in the right direction. I was intrigued by his acknowledgement that people who exercise a lot need additional protein to compensate for breakdown of branched chain amino acids, used as fuel during exercise. In his book "Paleo Diet for Athletes," he refers to saturated fats as "lethal." As for his views on fat consumption, perhaps he didn't want to get involved in the saturated fat and high fat diet controversies-- that would not suit his agendas. Or more charitably, perhaps he just doesn't want to go against mainstream advice in an area of knowledge that is not his specialty. I think like many, he pushes dietary carbs more than is necessary too (unlimited fruit and vegetables).

Stephan said...

Hi Cynthia and David,

I'm glad he acknowledges the increased protein requirements with exercise. My body craves much more protein when I'm lifting weights, so I never believed the people who claim you don't need any extra.

Well if sat fat is lethal, then I should be dead by now. I'll be getting a checkup sometime soon, so we'll see what my cholesterol, insulin, HbA1c etc looks like. Something tells me my numbers won't be pointing to imminent doom.

Chainey said...

"There's no way I'm going to cut the fat off my steak!"

Interesting coincidence that I should read this comment just now as today I had a novel thought: Imagine all the (fat) food value that's been cut, drained and paper-towel-patted out of food in the last 50 years, then imagine how many fewer animals would have had to be killed if that food value had been used. Of course the veg*ans don't want us to kill the animals at all, but if they were more pragmatic and took a harm-minimization approach (in their terms) they ought to be preaching the eating of the whole animal.

By the way, on the whale front, have a look at this article. Particularly, note the musculature of the hunters in the third photo. Guess they must have a good gym on their island.

Stephan said...

Chainey,

That is an awesome article! I didn't know there were Indonesian whaling cultures. Those people really do look sturdy, don't they?

AA said...

Those were fascinating pictures Chainey. I'm always telling people that it's healthy to eat animal fat and saying how healthy Inuit are. People generally reply that it is because the Inuit live in a cold environment. Yet these guys live in a hot environment and look to have hardly any body fat at all. With eskimos it's hard to tell what shape they are in while they wear their thick animal skin clothes.

Ryan said...

Great comments, especially the link to the whale hunters. I think with all of this it is important to remember that the diets of hunter-gatherers undergo tremendous seasonal variation, and of course the ratio of plant to animal foods varies tremendously according to climate. To me it makes sense that in certain colder climates, saturated fat intake during the winter might be very high as hunters utilize the fattest cuts from animals killed and then preserved during their fattest season (the fall).

Identifying a Paleolithic or Hunter-Gatherer Diet with restrictive macronutrient or animal to vegetable ratios seems unrealistic given these seasonal and regional variations. More importantly for us is to recognize that what almost all hunter-gatherer diets have in common is a low consumption of carbs (especially from grain), higher consumption of meat, and an active lifestyle.
I write extensively about the ways diet and nutrition can influence creativity at my website (http://creativesubstances.com), and I recently wrote an article about the Paleolithic diet and how its energizing effects can heighten creativity.

Ryan said...

Great comments, especially the link to the whale hunters. I think with all of this it is important to remember that the diets of hunter-gatherers undergo tremendous seasonal variation, and of course the ratio of plant to animal foods varies tremendously according to climate. To me it makes sense that in certain colder climates, saturated fat intake during the winter might be very high as hunters utilize the fattest cuts from animals killed and then preserved during their fattest season (the fall).

Identifying a Paleolithic or Hunter-Gatherer Diet with restrictive macronutrient or animal to vegetable ratios seems unrealistic given these seasonal and regional variations. More importantly for us is to recognize that what almost all hunter-gatherer diets have in common is a low consumption of carbs (especially from grain), higher consumption of meat, and an active lifestyle.
I write extensively about the ways diet and nutrition can influence creativity at my website, http://creativesubstances.com/, and I recently wrote an article about the Paleolithic diet and how its energizing effects can heighten creativity.

Rachel said...

The only problem I see with this is that our lifestyle has changed dramatically. We eat wheat-based foods as a major portion of our meals today, work in offices, and drive vehicles. We cannot base our health today on what humans ate when we lived as nomads.

It just doesn't work.