Ancestral Nutrition: An Alternative Approach

I gave that title to the talk I will give at the Ancestral Health Symposium this Friday morning at UCLA.

I wrote this description of it:

For about 65 million years our primate ancestors consumed plant-dominated diets. Humans developed the technological ability to consume meat-based diets only within the last 2 million years, so at least 98 percent of the evolution producing our basic primate physiology occurred before humans could obtain meat-based diets.

Condensing the 65 million years of primate evolution into a 24 hour period, our ancestral diet was plant-based for at least 23 hours and 30 minutes, and animal-based diets emerged only within the last 30 minutes.

Ninety-eight percent of the human genome is identical to the nearest primate relative, chimpanzees, who eat a 95 percent plant diet.  Recent hunter-gatherers consume up to 20 times more meat than chimpanzees on a percent energy basis, a substantial deviation from the primate baseline.     

Similar to other primates, humans retain many physiological and behavioral features displaying adaptation to a plant-based diet, some of which are potentially maladaptive for diets supplying a high proportion of energy from meat, fat, or refined carbohydrates.  Recent hunter-gatherers and pastoralists appear protected from maladaptive responses to animal-based diets by their baseline body composition, ecological context, low total energy intake, and evolved non-nutritive ingestive behaviors. 

Modern people adopting meat-based ‘paleo-facsimile” diets may differ from recent hunter-gatherers in lifetime caloric balance, body composition, ecological context, and non-nutritive ingestive behaviors.   By comparing hunter-gatherers and modern people, I show how the quality, quantity, and context of meat consumption will affect the outcome for any individual. 

Plant and animal foods generally have opposite yet complementary nutritional characteristics.  I present an integration of Chinese medical yin-yang theory with Western nutrition that can enable us to understand the relation each type of food (plant or animal) to modern diseases of deficiency or excess,  and can help guide us to identify an appropriate dietary plant-animal ratio for any individual.

 Time permitting, I plan to post a preview sometime later this week, and after the symposium, I will present the lecture in blog form.  

The Real Gladiator Diet

Source: U of Texas Course Intro To Greece

What did the gladiators eat?

According to Andrew Curry, author of "The Gladiator Diet," an article in the journal Archaeology, Karl Grossschmidt, a paleo-pathologist at the Medical University of Vienna, did an analysis of bones of gladiators found in an 1800 year old graveyard near Ephesus, in what is now western Turkey.

"Contemporary accounts of gladiator life sometimes refer to the warriors as hordearii--literally, "barley men." Grossschmidt and collaborator Fabian Kanz subjected bits of the bone to isotopic analysis, a technique that measures trace chemical elements such as calcium, strontium, and zinc, to see if they could find out why. They turned up some surprising results. Compared to the average inhabitant of Ephesus, gladiators ate more plants and very little animal protein."

Interesting.  The top athletes, with their lives on the line, ate 'very little' animal protein compared to non-athletes.  According to Grossschmidt, gladiators ate this way to get fat:

"The vegetarian diet had nothing to do with poverty or animal rights. Gladiators, it seems, were fat. Consuming a lot of simple carbohydrates, such as barley, and legumes, like beans, was designed for survival in the arena. Packing in the carbs also packed on the pounds. "Gladiators needed subcutaneous fat," Grossschmidt explains. "A fat cushion protects you from cut wounds and shields nerves and blood vessels in a fight." Not only would a lean gladiator have been dead meat, he would have made for a bad show. Surface wounds "look more spectacular," says Grossschmidt. "If I get wounded but just in the fatty layer, I can fight on," he adds. "It doesn't hurt much, and it looks great for the spectators."

What an interesting hypothesis.  Grossschmidt apparently believes that barley and beans are "simple carbohydrates" that "pack on the pounds" making people fat, and that a gladiator would prefer to be fat than lean and muscular.

I challenge Grossschmidt to consume a diet of barley and beans, with less than 10% of his diet as animal products, for a year, to find out if he grows fat eating that way.  Since cooked barley supplies only about 200 calories per cup, he can look forward to eating 6 cups daily just to get to 1200 kcal.  Add one cup of lentils (230 kcal), 4 cups of cooked kale (280 kcal), 4 ounces of sardines (240 kcal), and an ounce of almonds (180 kcal) and you have a nutritionally dense meal plan supplying about 2130 kcal and more than 11 cups of food.  See if you can eat it all, then enough additional to 'pack on the pounds.'

I also suggest that he produce some evidence that gladitors were fat.  He could spend a little time looking at reliefs and other art depicting gladiators of the time.  I found a good selection online from a University of Texas course, Introduction to Greece, here.  I put one of them at the head of this article.  Those men obviously have little subcutaneous or intra-abdominal fat, with ribs, rectus abdominus, deltoids, and upper back muscles clearly defined; they won't qualify as 'fat' by any standard.

Here are a few more from the same source:

Funny, I don't see any fat gladiators.  I didn't cherry-pick, you can look for yourself here.  These depictions don't look that much different from a modern vegetarian combat athlete, Chris Campbell, who won a bronze wrestling in the 1992 Olympics at age 37:

Source:  Information Processing

You can see how fat and weak Campbell got eating all those "simple sugars." 

I can't imagine any reason artists would falsely depict gladiators as lean and muscular, if they really were fat.  I wonder where Grossschmidt got his idea?

Grossschmidt apparently believes that "a lean gladiator would have been dead meat" compared to a fat one. I have to doubt that Grossschmidt has any experience in the fighting arts.  Fat slows you down, making you an easy target.  The goal of a gladiator was to survive, not to put on a good show; only a fool would choose to get fat for battles against armed opponents where you only walk away if you can move faster and hit harder than the other guy.

Grossschmidt also believes that those gladiators had to supplement calcium to their barley and vegetable diet:

"But a diet of barley and vegetables would have left the fighters with a serious calcium deficit. To keep their bones strong, historical accounts say, they downed vile brews of charred wood or bone ash, both of which are rich in calcium. Whatever the exact formula, the stuff worked. Grossschmidt says that the calcium levels in the gladiator bones were "exorbitant" compared to the general population. "Many athletes today have to take calcium supplements," he says. "They knew that then, too."

What? Despite having low animal protein intake, and eating a diet based on 'toxic' neolithic barley supplying much-feared gluten, phytates, and other "anti-nutrients" supposed to interfere with calcium absorption, these gladiators had 'exhorbitant' calcium levels in their bones?  Strong bones in agriculturalists?  How could that happen?

Well, let's see if they needed calcium supplements.  Ephesus lies on the west coast of Turkey, near the mouth of the Menderes River, so I will assume the gladiators ate some fish.  I'll build the diet of barley, lentils, kale, olives, acorns, and sardines, all possible foods for those people.  Here's a nutritional analysis of a hypothetical barley diet with less than 10% of calories from sardines:

Click to Enlarge

As you can see, to get to 3400 kcal required by a large, physically active martial artist using swords, tridents, and similar arms, the barley men would have to eat 10 cups of cooked barley in a day.  Now imagine having to eat several more daily to 'pack on the pounds.'  Good luck with that!

With only 4 ounces of sardines (supplying only 236 calories, less than 10% of total) and two cups of lentils, it supplies 116 g of protein, enough for a 220 pound athlete.  The diet supplies energy in the following  proportions: 70/18/12, carbohydrate/fat/protein. It supplies all required nutrients in adequate amounts (most nutrients at 2-4 times the RDA) except vitamin E, which is 77% of RDA, probably adequate for most people eating a diet this low in fat (71 g/d), but we could boost this by exchanging one cup of  barley for one cup of olives (that brings the vitamin E to 97% of RDA and fat to 22% of calories). 

I also tested 3000 calories of this diet by removing 2 cups of barley.  It became 67/20/13 (carb/fat/pro) and still supplied 110 g protein, enough for a 220 pound athlete.  It still supplied at least 100% of the RDA for all listed nutrients except vitamin E, still at 77%.

Now, back to the 'exorbitant' levels of calcium in these athlete's bones. First, ancient athletes were familiar with resistance training, using all types of heavy objects to increase strength.   Physical training with heavy weapons and other sources of resistance stresses the bones, increasing mineral deposition, so we should expect athletes like gladiators to have high bone mineral density.

Second, humans appear to absorb more calcium from some plants, especially cabbage-family green leafy vegetables, than from milk.  In one study humans absorbed a greater proportion of calcium from kale (and probably similar brassica vegetables) (41%) than from milk (32%) [1]. As an aside, Heaney et al found that humans absorbed calcium from leavened whole wheat bread at at higher rate than from milk [2].

Third, we have evidence from other paleo diet research suggesting that a diet with a high ratio of plant to animal protein may promote greater bone mineral density.  Richman et al compared bones of three aboriginal American populations:  Pueblos, Arikaras, and Inuit [3 ].   These groups had similar genetic backgrounds, all descended from the few humans who first populated the Americas. 

Richman et al looked for type II osteons, characteristic of increased bone mineral resorption involved in maintaining physiological homeostasis, such as buffering to maintain the pH of urine in the range safe for kidney tubules.  They found that the Pueblos had the least evidence of this type of remodeling, and Eskimos had four times as many type II osteons as the Pueblos.  The diet of the Pueblos consisted largely (80%) of maize and 90% of plant foods, while the Eskimo diet consisted 90% of meat.  The Arikaras consumed more meat than Pueblo and less than Eskimos, and had twice as many type II osteons the Pueblos.

When I first reviewed this study, I missed the fact that it contradicted the theory that people are less adapted to grains than to meat.  If the antinutrients in grains impair calcium and vitamin D metabolism, the Pueblos should have had the worst bone health because they had the highest cereal grain intake, supposedly blocking vitamin D action and calcium absorption; but in fact they had the lowest markers of resorption. 

We have plenty of evidence that isolated Inuit had severe and early onset osteoporosis [4, 5].  Similar to the Pueblos, largely vegetarian Bantu women eating grain-based diets have extremely low rates of osteoporosis despite very low (200-450 mg/d) intakes of calcium and a high number of pregnancies (~10 per woman) with prolonged breastfeeding [6 ]. 

We have some evidence that a diet with a high ratio of animal protein to vegetable protein increases urinary calcium losses and that this may result in demineralization of the bones [7 , 8 , 9 , 10, among others].  While some consider this research inconclusive so far [11], it seems to me that the bulk of research points in the direction of diets with high ratios of animal protein increasing the risk of bone mineral loss, although the mechanism may be unclear and other factors may modify this risk (resistance training, vitamin D, vitamin K, dietary acid-base ratio, sodium intake, to name a few).  Anyway, it appears possible that the gladiators' high ratio of vegetable to animal protein contributed to their maintaining a high bone mineral density. 

I conclude that a diet of barley, lentils, olives, acorns, green vegetables, and small amount of small fish can provide plenty of calcium, which when combined with hard physical training will produce very dense, strong bones.  Maybe those gladiators did add wood ash or bone meal, but they may have been overdosing on unnecessary calcium, the same way the many modern athletes take unnecessary supplements hoping for greater performance.