Are humans designed
to eat meat?
Meat consumption causes the human body many problems; from decreased energy, a need for more sleep up to increased risk for obesity, diabetes, heart disease, and cancer.
Given that meat does not have these devastating effects on other species, namely the carnivorous species, it raises the question: "are humans designed to eat meat?"
The following will explain...
Shattering the meat myth: Humans are natural vegetarians
Dr. T. Colin Campbell, professor emeritus at Cornell University and author of The China Study, explains that in fact, we only recently (historically speaking) began eating meat, and that the inclusion of meat in our diet came well after we became who we are today. He explains that "the birth of agriculture only started about 10,000 years ago at a time when it became considerably more convenient to herd animals. This is not nearly as long as the time [that] fashioned our basic biochemical functionality (at least tens of millions of years) and which functionality depends on the nutrient composition of plant-based foods."
That jibes with what Physicians Committee for Responsible Medicine President Dr. Neal Barnard says in his book, The Power of Your Plate, in which he explains that "early humans had diets very much like other great apes, which is to say a largely plant-based diet, drawing on foods we can pick with our hands. Research suggests that meat-eating probably began by scavenging--eating the leftovers that carnivores had left behind. However, our bodies have never adapted to it. To this day, meat-eaters have a higher incidence of heart disease, cancer, diabetes, and other problems."
There is no more authoritative source on anthropological issues than paleontologist Dr. Richard Leakey, who explains what anyone who has taken an introductory physiology course might have discerned intuitively--that humans are herbivores. Leakey notes that "[y]ou can't tear flesh by hand, you can't tear hide by hand.... We wouldn't have been able to deal with food source that required those large canines" (although we have teeth that are called "canines," they bear little resemblance to the canines of carnivores).
In fact, our hands are perfect for grabbing and picking fruits and vegetables. Similarly, like the intestines of other herbivores, ours are very long (carnivores have short intestines so they can quickly get rid of all that rotting flesh they eat). We don't have sharp claws to seize and hold down prey. And most of us (hopefully) lack the instinct that would drive us to chase and then kill animals and devour their raw carcasses. Dr. Milton Mills builds on these points and offers dozens more in his essay, "A Comparative Anatomy of Eating."
The point is this: Thousands of years ago when we were hunter-gatherers, we may have needed a bit of meat in our diets in times of scarcity, but we don't need it now. Says Dr. William C. Roberts, editor of the American Journal of Cardiology, "Although we think we are, and we act as if we are, human beings are not natural carnivores. When we kill animals to eat them, they end up killing us, because their flesh, which contains cholesterol and saturated fat, was never intended for human beings, who are natural herbivores."
Sure, most of us are "behavioral omnivores"--that is, we eat meat, so that defines us as omnivorous. But our evolution and physiology are herbivorous, and ample science proves that when we choose to eat meat, that causes problems, from decreased energy and a need for more sleep up to increased risk for obesity, diabetes, heart disease, and cancer.
Old habits die hard, and it's convenient for people who like to eat meat to think that there is evidence to support their belief that eating meat is "natural" or the cause of our evolution. For many years, I too, clung to the idea that meat and dairy were good for me; I realize now that I was probably comforted to have justification for my continued attachment to the traditions I grew up with.
But in fact top nutritional and anthropological scientists from the most reputable institutions imaginable say categorically that humans are natural herbivores, and that we will be healthier today if we stick with our herbivorous roots. It may be inconvenient, but it alas, it is the truth. [1]
The comparative anatomy of eating
A presentation by Milton Mills, M.D.
The major causes of death in Western countries are cardiovascular diseases and cancers. Abundant medical research linking these diseases to dietary and lifestyle factors, guidelines advanced by the American Heart Association, the American Cancer Society, and the Surgeon General, among others, counsel Americans to sharply reduce animal foods consumed and replace them with fruits, vegetables, and whole grains. In effect, they are recommending a more plant-based diet, which begs the question:
Are humans designed to eat meat?
Milton Mills, M.D. has an extensive background in nutrition research, focusing on the role nutrition plays in the development of chronic diseases. He is a graduate of the Stanford University School of Medicine and is a practicing physician in the Washington, D.C. area. He also serves as the Associate Director of Preventive Medicine for the health policy group Physicians Committee for Responsible Medicine. He has lectured extensively throughout North America and is a Nutrition Health Education Video Spokesperson for the Discovery Health Channel.
The following is the introduction, human characteristics, comparative outline, and conclusion of Dr. Milton R. Mills’ analysis of human anatomy and physiology: “The Comparative Anatomy of Eating”:
Beliefs
Humans are most often described as “omnivores.”
This classification is based on the “observation” that humans generally eat a wide variety of plant and animal foods. However, culture, custom and training are confounding variables when looking at human dietary practices.
Thus, “observation” is not the best technique to use when trying to identify the most “natural” diet for humans. While most humans are clearly “behavioral” omnivores, the question still remains as to whether humans are anatomically suited for a diet that includes animal as well as plant foods.
Facts
A better and more objective technique is to look at human anatomy and physiology.
Mammals are anatomically and physiologically adapted to procure and consume particular kinds of diets. It is common practice when examining fossils of extinct mammals to examine anatomical features to deduce the animal’s probable diet.
Therefore, we can look at mammalian carnivores, herbivores (plant-eaters) and omnivores to see which anatomical and physiological features are associated with each kind of diet. Then we can look at human anatomy and physiology to see in which group we belong.
Human herbivores?
Gastrointestinal tract
The human gastrointestinal tract features the anatomical modifications consistent with an herbivorous diet. Humans have muscular lips and a small opening into the oral cavity. Many of the so-called “muscles of expression” are actually the muscles used in chewing. The muscular and agile tongue essential for eating, has adapted to use in speech and other things. The mandibular joint is flattened by a cartilaginous plate and is located well above the plane of the teeth. The temporalis muscle is reduced. The characteristic “square jaw” of adult males reflects the expanded angular process of the mandible and the enlarged masseter/pterygoid muscle group. The human mandible can move forward to engage the incisors, and side-to-side to crush and grind.
Teeth
Human teeth are also similar to those found in other herbivores with the exception of the canines (the canines of some of the apes are elongated and are thought to be used for display and/or defense). Our teeth are rather large and usually abut against one another. The incisors are flat and spade-like, useful for peeling, snipping and biting relatively soft materials. The canines are neither serrated nor conical, but are flattened, blunt and small and function like incisors. The premolars and molars are squarish, flattened and nodular, and used for crushing, grinding and pulping noncoarse foods.
Saliva
Human saliva contains the carbohydrate-digesting enzyme, salivary amylase. This enzyme is responsible for the majority of starch digestion. The esophagus is narrow and suited to small, soft balls of thoroughly chewed food. Eating quickly, attempting to swallow a large amount of food or swallowing fibrous and/or poorly chewed food (meat is the most frequent culprit) often results in choking in humans.
Stomach
Man’s stomach is single-chambered, but only moderately acidic. (Clinically, a person presenting with a gastric pH less than 4-5 when there is food in the stomach is cause for concern.) The stomach volume represents about 21-27% of the total volume of the human GI tract. The stomach serves as a mixing and storage chamber, mixing and liquefying ingested foodstuffs and regulating their entry into the small intestine. The human small intestine is long, averaging from 10 to 11 times the body length. (Our small intestine averages 22 to 30 feet in length. Human body size is measured from the top of the head to end of the spine and averages between two to three feet in length in normal-sized individuals.).
Colon
The human colon demonstrates the pouched structure peculiar to herbivores. The distensible large intestine is larger in cross-section than the small intestine, and is relatively long. Man’s colon is responsible for water and electrolyte absorption and vitamin production and absorption. There is also extensive bacterial fermentation of fibrous plant materials, with the production and absorption of significant amounts of food energy (volatile short-chain fatty acids) depending upon the fiber content of the diet. The extent to which the fermentation and absorption of metabolites takes place in the human colon has only recently begun to be investigated.
Conclusion
In conclusion, we see that human beings have the gastrointestinal tract structure of a “committed” herbivore. Humankind does not show the mixed structural features one expects and finds in anatomical omnivores such as bears and raccoons. Thus, from comparing the gastrointestinal tract of humans to that of carnivores, herbivores and omnivores we must conclude that humankind’s GI tract is designed for a purely plant-food diet. [2]
To read the document containing the complete analysis by Dr. Milton R. Mills, please click here!