Health and Diet
Humans: High Trophic Level Carnivores (not Omnivores or Herbivores)
Updated - 02 Jan 21
‘Man the Fat Hunter’ – Humans are a unique high trophic level carnivore!
The research of Dr Miki Ben-Door PhD, one of the world’s leading paleoanthropologists, led to his excellent paper entitled ‘Man the Fat Hunter: The Demise of Homo erectus and the Emergence of a New Hominin Lineage in the Middle Pleistocene (ca. 400 kyr) Levant.’ [i]
In this work, Dr Ben-Dor examined anthropological and physiological evidence to determine what the most likely drivers behind the replacement of H.Erectus by H.Sapien were. Simply put, stone age humans were physiologically dependent on a very specific diet, high in animal fat, due to having a smaller liver (and other protein processing infrastructure) than other carnivores. This dependence on fat, and the demise of the highly fatty megafauna of the late Pleistocene, meant that only a ‘lighter, more agile and cognitively capable hominin’ could survive.
Modern humans are a unique carnivore hunter that specifically targets the animals that carry the most fat. Unlike modern canines and felines who catch what they can, often the sick, old or young with low fat stores, humans have hunted the prime animals. While having, in terms of gut surface area an almost identical digestive capacity compared to body weight to canines (wolves, dogs, coyotes, etc), humans are equipped with much smaller livers. This limits our ability to process protein through liver glycolysis and precludes us surviving on the lean animals that canines and felines do.
While no exact limit on protein consumption is known, with 35-45% of total calories being a commonly discussed range, it is clear that a food source too rich in protein and too low in fat results in a condition known as ‘rabbit starvation’.
This reliance on fat is so ingrained in human history that many cultures and languages equate fat to health, wealth and wellbeing. Not ‘being fat’, but ‘having enough fat’. Unfortunately, our modern plant-based diet has replaced eating fat with getting fat, with all the attendant metabolic disease we see in western society.
Interestingly, Neandertal remains show a different rib cage structure to modern humans. Their rib cage was bell shaped, opening the hypothesis that Neandertals had larger livers and may have had a considerably higher protein limit. Their physiques were adapted to greater bursts of strength and speed over short distances, compared with modern humans and their upper body structure more suited to thrusting with a spear than throwing. In addition, their cranial structure indicates that they may have had a higher IQ than modern humans with respect spatial reasoning giving them advantage in ‘mapping’ and navigation.
These characteristics, perhaps, are an indication that they were intercept or ‘ambush’ hunters, rather than persistence hunters.
Their spatial intelligence, raw strength and short distance speed would have been an advantage in rough and/or forested terrain and against larger prey species but a disadvantage in open savannah with smaller, swifter prey.
I’m not too sure what to conclude from these facts, but it would seem that the ability to eat leaner animals, if that’s what the Neandertal rib cage shape indicates, did not make up for the relative lack of endurance compared to modern humans as larger megafauna disappeared during late Pleistocene.
What did humans eat before they invented autoimmune disease, cardiovascular disease and cancer?
The bottom line – Humans are ‘high trophic level facultative carnivores’, from a physiological standpoint. Dr Miki Ben-Dor has presented twelve separate human physiological adaptations toward carnivory, including three that specialise away from plant-based foods. Simply put, not only are we very well adapted to eating meat, specifically fatty meat, as our dietary staple, several of the adaptations to eating meat seriously hinder our ability to exploit plant-based nutrients, even for survival purposes. In addition, we have one physiological adaptation that precludes concurrent consumption of animal proteins/fats and plant-based carbohydrates without serious negative health consequences, making the claim that we are historically or physiologically omnivorous a claim that contradicts the scientific evidence.
This adaptation is unsurprising as humans have been Paleolithic hunter gatherers for 99.4% of human history and Neolithic farmers for only 0.6% of human history. During that time, we lived primarily on seasonally humid grassland savannahs where animals were the only edible source of nutrition for half the year or more. During the wet/growing season, only small quantities of digestible fruits, berries and vegetables were available. Perhaps enough to provide a sweet distraction during a hunt for real food, but insufficient to provide more than short term sustenance.
The detail - To answer this question in depth, we need to look at human physiology, morphology and the environment humans occupied before the Neolithic.
Human Physiology. There are many features of human physiology that support the claim that humans are facultative carnivores, not herbivores or even omnivores.
The gut. The human digestive system is very different from other primates. Compared to orangutans, chimps and gorillas of similar body size, the human small intestine is 3 times longer and the human colon is 70% shorter than the great apes.
- In terms of gut surface area to body mass, the human gut is closer to that of a wolf or dog than it is to the herbivorous great apes.
- Small intestine – This component of the gut is specialised in digesting highly nutrient dense foods such as meat and fat.
- Large intestine – This component of the gut is specialised in digesting low nutrient density plant-based foods.
- The proportions of the human gut indicate high density animal products as the primary source of nutrients and calories, with only a residual survival capacity for digesting plants.
- Human stomach acidity. Stomach acidity is an indication of diet in most animals. Herbivores have a low acidity stomach (PH – 4.2 to 7.3), Omnivores medium acidity (PH – 2.1 to 3.7), Carnivores quite acidic (PH – 1.2 to 3.6) and Scavangers very acidic (PH – 1.0 to 1.8). High stomach acidity helps animals defeat pathogens in the food source but has the cost of being highly energy intensive to sustain. [ii]
- Human stomach PH is 1.0 to 3.0, highly acidic and comparable to vultures, hyenas and buzzards, effectively being a scavenger level of acidity.
- Unlike other carnivores, Paleolithic humans hunted larger animals and store their meat for extended periods, consuming it over time. This form of hunting enabled higher pathogen loads to develop in our food sources, requiring a stomach PH similar to scavengers.
- Erect bipedal phenotype. Compared to the great apes, humans are taller, slimmer and have longer legs and an extremely complex lower leg physiology specifically structured for efficient long-distance travel.
- Below 5 kph, human males are more energy efficient that equivalent quadrupeds, and female humans experience an even greater calorific saving. In fact, bipedal energy costs fall below quadrupeds at all rates between 2.4 and 6 kph, the natural walking speed of humans, matching carnivorous home range metabolic requirements for carnivores with the highest meat intake as a percentage of diet. [iii]
- For distances over 40km (25 miles), humans are the fastest terrestrial mammal in tropical climates and only equalled by canines in cooler temperate climates.
- Predators have relatively large home ranges, needing to travel greater distances than herbivores to obtain their food.
- Human physiology, combined with intelligence, uniquely allows a form of hunting known as ‘persistence hunting’. This form of hunting is still practiced by some Paleolithic societies, where the hunters single out one prey animal and run it to exhaustion over a period of several hours. Only wolves display the capacity for persistence hunting and only in temperate/arctic climates, whereas humans retain this capacity in all climatic regions. [iv]
- Human shoulder physiology. Humans have a unique shoulder physiology specifically adapted to throwing. [v]
- This has both a defensive purpose, throwing objects at other predators, and a hunting purpose, where objects/weapons are thrown at prey to immobilise/kill it.
- This physiological adaptation is a specialisation that reduces our ability to seek out plant-based nutrition as it hinders our ability to climb trees. A chimpanzee can climb extremely well, but would struggle to throw a tennis ball 30 ft.
- Given that many species are much better adapted to obtaining fruit and nuts, it is logical to assume that any adaptation that hinders our ability to obtain these plant-based food sources in favour of obtaining meat is evidence of specific adaptation to carnivory.
- Brain size. Human brains are, in relation to our body size, about 900cc too large for a herbivorous diet.
- The brain and the gut are highly energy expensive organs. The upper limit of metabolic performance is approximately 2.5x the basal metabolic rate (that energy required to stay alive at rest).
- With energy generation limited, a larger gut requires a smaller brain and vice versa. In order to sustain a larger brain with a smaller gut, humans are finely tuned to consume calorie and nutrient dense animal foods as opposed low nutrient density plant foods.
- Fat storage capacity. Humans retain the capacity to store significant amounts of body fat compared with other animals.
- Humans display much higher fat reserves than our closest genetic relative, the chimpanzee. [vi]
- High fat storage capacity allows long breaks between hunts. [vii]
- Fat cell structure. Human adipocyte (lipocytes / fat cells) size and number indicate a carnivorous rather than herbivorous or omnivorous diet. Carnivores display a higher number of smaller fat cells and omnivores display a smaller number of larger fat cells.
- Human adipocyte structure places humans at the top of the carnivorous range. [viii]
- Dietary inflammation. Human physiology reacts quite negatively to concurrent consumption of carbohydrates and fats, with inflammation and autoimmune disease rapidly increasing.
- This is an indication that early humans survived predominantly on meat and only ate plants for survival during times of scarcity.
- As naturally occurring plant-based foods are often quite toxic and, while calorie rich, are nutrient deficient, it is clear that Paleolithic humans would only have turned to them for short periods of time until nutrient dense animal foods could be reacquired.
- Jaw structure. The human jaw structure, and in particular the mandible, has been too small to support a herbivorous diet for at least 1.8 million years (appearance of H.Erectus).
- This reduction in mastication capacity matches the difference between human and ape gut morphology during the same period and is a clear indication that humans have been a high trophic level carnivore, living on a nutrient dense animal-based diet, for the majority of our existence on earth. [ix]
- Infant Weaning. The life history (gestation length, weaning, mating and death) of a species is strongly defined. A comparison of infant weaning places humans in the category of carnivore, whereas the great apes and other primates match non-carnivore patterns.
- The discoverers of this phenomenon postulate that the closer the nutrient profile of the post-weaning diet is to the nutrient profile of breast milk, the shorter the transition from milk to external foods. ‘Our findings highlight the emergence of carnivory as a process fundamentally determining human evolution.’ [x]
- Incomplete adaptation to starch metabolism. Humans display a varying number of allele variations for the AMY1 gene which synthesise salivary amylase. This results in many differing degrees of adaptation to the digestion of starches and is an indication that the adaptation to digesting starches is both incomplete and relatively recent, genetically speaking. [xi]
- Recent and regionally limited adaptation to tuber consumption. Tubers are often mentioned as a good candidate for Paleolithic plant-based dietary staples. However, populations that currently depend on tubers show enriched genetic diversity in genes associated with starch metabolism, folic acid synthesis and glycoside neutralisation. Many other populations display little or none of this genetic adaptation to the low folic acid and high glycoside content of tubers.
- The limited geographic distribution of these genes is a good indication that these adaptations are recent and, self-evidently, incomplete. [xii]
Not only do these adaptations give a clear pattern of human carnivory, but several of them are adaptations AWAY from plant consumption. Our gut morphology, jaw structure, shoulder structure and autoimmune system are all adapted away from plant consumption, either reducing our ability to obtain nutrients from plant sources, or worsening the health consequences of doing so.
Anthropological Evidence. In addition to human physiological adaptation, there are a number of sources of anthropological evidence that humans are uniquely adapted to carnivory and away from herbivorous or omnivorous diets.
- Evidence of dental cavities. A high prevalence for cavities (caries) is an indication of intensive consumption of carbohydrates, necessary calories on a plant-based diet.
- `The earliest human tooth remains displaying cavities, together with other evidence for the exploitation of starchy foods, appears in Morocco 15,000 years ago. [xiii]
- The oldest H.Sapien jaw remains date to 300,000 years ago and display a perfect set of teeth. This pattern is repeated and typical through the Paleolithic period. [xiv]
- This evidence is indication that the consumption of significant quantities of plant-based food is a relatively recent phenomenon; only the last 15,000 years out of the last 1.8 million years of human anthropological history.
- Nitrogen isotope profiles. In animal remains where collagen can be found, a period of defined by the last 50,000 years or so, the nitrogen isotope 15 (δ15N) levels can be used to determine carnivores from omnivores and herbivores. The greater the consumption of animal products, the higher the levels of δ15N found in the collagen.
- One study found that remains of H.Neandertalis (Neandertals) and H.Sapiens (Modern Humans) showed levels of δ15N that exceeded those of other carnivores in the same region, including some obligatory carnivores such as cats. [xv]
- This study also highlighted that modern humans had the same or higher meat consumption than the Neandertals in the same region, indicating that both were high trophic level carnivores.
- Despite the evidence of higher δ15N levels than obligatory carnivores, the well-established ability for humans to adapt to plant-based food sources for short periods of time, precludes placing humans in the category of ‘obligatory carnivores’. The evidence suggests humans are high trophic level ‘facultative carnivores’.
- Evidence of autoimmunity and other disease. The Neolithic revolution and, in particular, the domestication of plants for human consumption, resulted in an explosion of ‘diseases of civilisation’, among which are coronary heart disease, obesity, hypertension, type 2 diabetes, metabolic cancers, autoimmune disease (arthritis, celiac, intolerances, Alzheimer’s, Parkinsons, etc), osteoporosis, dental decay and others.
- These diseases were, and remain, rare in paleolithic hunter-gatherer societies.
- These diseases can be traced to the consumption of seed oils and/or plant toxins and/or the sustained consumption of plant carbohydrates. As previously discussed, plant based foods result in chronic malnutrition, inhibiting the human body’s ability to deal with the deleterious effects of these Neolithic ‘foods’. [xvi] [xvii]
- The effect of plant-based Neolithic agriculture on human health has been so profound that archeologists can use evidence of arthritis or dental cavities to differentiate between Neolithic and Paleolithic remains.
Arable plant-based agriculture. While not having a direct impact on human health, the ecological destruction and indirect downstream health effects of arable plant-based agriculture must also be discussed.
Ecological damage and habitat destruction. Arable plant-based agriculture is the single most destructive industry on earth regarding ecological damage and wildlife habitat destruction. Of all the products grown by arable agriculture, rice, cotton and soybeans are the three most destructive crops. A healthy ecosystem has an effective mineral cycle, hydrological (water) cycle, energy (carbon) cycle and effective community dynamics (microbe/plant/animal symbiosis).
The reasons for its destructive properties are:
Neolithic farming is an extractive system, taking resources from the natural world without replacing them. Modern industrialised agriculture is Neolithic farming with more horsepower and GPS. The natural environment cannot heal the damage caused by cropping as quickly as it occurs.
Monocultures. Arable agriculture is based around monocultures. Monocultures are extremely rare in nature. As the technical definition of desertification is the loss of biodiversity, arable agriculture involves deliberate desertification.
A plant monoculture does not support a healthy soil ecosystem. Microbial biodiversity reduces in monocultures, reducing soil nutrient conversion from parent material to bio-available forms. Over time, monoculture agriculture destroys the soil ecosystem rendering soil an inert medium and the response of industrialised Ag is to replace natural nutrients with synthetics.
Plant monocultures do not support above ground biodiversity. No mammal species can survive in a plant monoculture and few insect species. Absent the balance of a diverse ecosystem, normally banal plants, animals, insects, molds, fungi, etc can become destructive pests/weeds. Their control requires greater and greater use of pesticides, fungicides, and herbicides, further damaging healthy microbes in the soil and accelerating the decline of the ecosystem.
Reduction in energy and mineral cycling and community dynamics.
Exposed soil. Arable agriculture often results in soil exposed to direct sunlight and precipitation. When soil is exposed to direct sunlight it overheats, resulting in moisture lost to evaporation and soil microbiology being killed off. Soil exposed to direct precipitation results in erosion and the formation of crusts which prevent moisture infiltration.
Reduction in mineral and water cycling.
Short growing season. Annuals grown in monocultures result in a living root growing in the soil for a limited period in each growing season.
Reduction in mineral, water and energy cycling.
Disturbed soil ecosystem. Arable agriculture is based on early succession annuals, plants that re-seed each year and whose natural ecological role is to rapidly cover up exposed or damaged soil until perennial plants can recover. Therefore, growing these plants requires mechanical disturbance (tillage) or chemical disturbance (herbicides) to maintain stop the encroachment of undesirable species of plants. This disturbance damages the soil ecosystem, tearing up and destroying microbe and fungal communities required for healthy soil ecosystem processes.
Reduction in mineral and water cycling and community dynamics.
No animals. Plant based food production does not integrate animals. In every natural environment now used for agricultural production, animals are essential components of the functioning ecosystem. In many cases, particularly in seasonally humid regions, animals are essential for the survival of the plant ecosystem and cycling biomass back into the soil. Without the animals, above ground biomass oxidises, smothers new growth and is not made available to soil microbiology.
Reduction in mineral, water and energy cycle and poor community dynamics.
The result of these impacts on the natural ecosystem is a loss of biodiversity, the loss of the topsoil ecosystem and the degradation of soil nutrients. It is simply mining with plants, a one-way extractive process. The use of mechanised agricultural equipment, synthetic fertiliser, herbicides, pesticides, and fungicides simply accelerates the process started 12,000 years ago. Modern industrialised agriculture is very energy and chemically intensive. Humans currently cause around 75 billion tonnes of topsoil loss every year, 20 times more soil mass than food mass required for every human alive on earth.
One consequence of the degradation of topsoil is a loss of nutrient density, even in plant foods. In the US, nutrient density was 50% higher in 1950 than the present day. Corn that was once 9% crude protein is now only 6%. We’re producing more calories, but less nutrition than ever before.
In 2015, scientists at the UN’s Food and Agriculture Organization concluded that, at current loss rates, the world’s topsoil had as few as 60 harvests left before our agricultural system failed. This is a doomsday prediction with very little supporting evidence in the peer-reviewed literature (one paper from the University of Sheffield is the sum total of the supporting literature), but there is no doubt that the world would be better off if we did agriculture differently.
Finally, this whole industry is a massive carbon emitter. The absolute best of modern no-till ‘sustainable’ plant-based agriculture is only just carbon neutral and many crops (rice, soybeans, peas, beans, lentils, cotton and most vegetable production) are impossible to grow in a carbon negative monoculture system.
When one combines this ecological damage, a lack of nutrient density and the increase in synthetic chemicals, in the form of pesticide and herbicide residues, left both in the environment and our food by plant-based food production, there is little argument left for plant-based food.
[i] Miki Ben-Dor, Avi Gopher, Israel Hershkovitz, Ran Barkai. Man the Fat Hunter: The Demise of Homo erectus and the Emergence of a New Hominin Lineage in the Middle Pleistocene (ca. 400 kyr) Levant. December 9, 2011 PLoS ONE 6(12): e28689.
[ii] Beasley DE, Koltz AM, Lambert JE, Fierer N, Dunn RR. The evolution of stomach acidity and its relevance to the human microbiome. PLoS ONE. 2015;10(7): e0134116.
[iii] Gittleman JL, Harvey PH. Carnivore home-range size, metabolic needs and ecology. Behav Ecol Sociobiol. 1982;10(1):57-63.
[iv] Bramble DM, Lieberman DE. Endurance running and the evolution of Homo. Nature. 2004;432(7015):345-52
[v] Roach NT, Venkadesan M, Rainbow MJ, Lieberman DE. Elastic energy storage in the shoulder and the evolution of high-speed throwing in Homo. Nature. 2013;498(7455):483-6.
[vi] Zihlman AL, Bolter DR. Body composition in Pan paniscus compared with Homo sapiens has implications for changes during human evolution. Proceedings of the National Academy of Sciences. 2015:201505071.
[vii] Pontzer H, Raichlen Wood BM, Emery Thompson M, Racette SB, Mabulla AZ, et al. Energy expenditure and activity among Hadza huntergatherers. Amer J Hum Biol. 2015;27(5):628-37.
[viii] Pond CM, Mattacks CA. Body mass and natural diet as determinants of the number and volume of adipocytes in eutherian mammals. J Morphol. 1985;185(2):183-93.
[ix] Lucas PW, Sui Z, Ang KY, Tan HTW, King SH, Sadler B, et al. Meals versus snacks and the human dentition and diet during the Paleolithic. The Evolution of Hominin Diets: Springer; 2009. p. 31-41.
[x] Psouni E, Janke A, Garwicz M. Impact of carnivory on human development and evolution revealed by a new unifying model of weaning in mammals. PLoS ONE. 2012;7(4):e32452.
[xi] Perry G, Dominy N, Claw K, Lee A. Diet and the evolution of human amylase gene copy number variation. Nature. 2007;39(10):1256.
[xii] Hancock AM, Witonsky DB, Ehler E, Alkorta-Aranburu G, Beall C, Gebremedhin A, et al. Human adaptations to diet, subsistence, and ecoregion are due to subtle shifts in allele frequency. Proceedings of the National Academy of Sciences. 2010;107(Supplement 2):8924-30.
[xiii] Humphrey LT, De Groote I, Morales J, Barton N, Collcutt S, Ramsey CB, et al. Earliest evidence for caries and exploitation of starchy plant foods in Pleistocene hunter-gatherers from Morocco. Proceedings of the National Academy of Sciences. 2014;111(3):954-9.
[xiv] Hublin J-J, Ben-Ncer A, Bailey SE, Freidline SE, Neubauer S, Skinner MM, et al. New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens. Nature. 2017;546(7657):289.
[xv] Klervia Jaouen, Michael P. Richards, Adeline Le Cabec, Frido Welker, William Rendu, Jean-Jacques Hublin, Marie Soressi, and Sahra Talamo. Exceptionally high δ15N values in collagen single amino acids confirm Neandertals as high-trophic level carnivores. PNAS March 12, 2019 116 (11) 4928-4933; first published February 19, 2019
[xvi] Latham, Katherine J., "Human Health and the Neolithic Revolution: an Overview of Impacts of the Agricultural Transition on Oral Health, Epidemiology, and the Human Body" (2013).Nebraska Anthropologist. 187.
[xvii] Pedro Carrera-Bastos, Maelan Fontes-villalba, James H O’Keefe, Staffan Lindeberg, Loren Cordain. The western diet and lifestyle and diseases of civilization. 08 March 2011, Dove Press Journal; Research Reports in Clinical Cardiology.
More reference material:
Ben-Dor, M. (2018). How carnivorous are we? The implication for protein consumption. Journal of Evolution and Health: A joint publication of the Ancestral Health Society and the Society for Evolutionary Medicine and Health, 3(1).
‘Neanderthin’ by Ray Audette
‘The Carnivore Code’ by Dr Paul Saladino MD
‘The Carnivore Diet’ by Dr Shawn Baker MD
‘Holistic Management’ by Alan Savory (First/second Editions contain more scientific background than the third edition, which focus more on management processes.)
‘Eat Rich Live Long’ by Ivor Cummins & Jeffry Gerber MD
‘Grass Productivity’ by Andre Voisin
‘Dirt to Soil’ by Gabe Brown
‘Folks, This Ain’t Normal: A Farmer’s Advice for Happier Hens, Healthier People and a Better World’ by Joel Salatin
‘Salad Bar Beef’ by Joel Salatin
‘Everything I Want To Do Is Illegal: War Stories from the Local Food Front’ by Joel Salatin