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The Vegan vs. Omnivore Debate Part 4

Updated on November 8, 2012

Digestive Anatomical Differences

Without trying to get too "sciency" on you, there are several issues in this second-last part of the Debate that I would like to address. These include digestive anatomical differences and health between humans and true herbivores. First though, because I may come across as biased about the facts of being a true omnivore and not a herbivore, I would like to say this: We humans are true omnivores. And many vegans get up on their high-horse about that. I will tell you why and explain the facts in comparisons with the true herbivores that exist today.

Stomach Anatomy

We humans are monogastrics. This means that we have a simple stomach designed to break down amino acids, starch and carbohydrates more efficiently than fibrous material found in grains and other plant material. Vegans argue that the length of time meat is digested in our stomachs versus vegetables and fruit--meat takes longer to digest than fruit/vegetables do--means that our stomachs are less efficient at digesting meat. Now let me get on my science chair for a minute here: This is false. Plant material containing fibre, cellulose and hemi-cellulose cannot be efficiently broken down by the peptides and other enzymes our stomachs secrete that makes digesting meat and carbohydrates more efficient. Cows, on the other hand, are more efficient at digesting plant matter because they have multiple chambers in their stomach, and they have microbes in their rumen that enables the break down of fiber and cellulose from plant tissue that is tougher than the stuff we humans eat or are capable of eating. This material, for us, only acts as a "gut filler" making us feel full, yet we are not really getting much nutrition out of it. Plant material is said to pass through more slowly than meat. This is also false. Plant material actually passes through much faster than meat because, as mentioned before, not much nutrition can be gleaned from such foodstuffs. It's a different story with animal products. Meat is in our stomach "so long" because the stomach can efficiently digest it enough that more nutrients are gleaned from this food source than with plants. The same thing goes for carbohydrate and starch-type foods. The length of digestion in our stomach is really similar to that of other non-human omnivores and carnivores. Because of that, humans are not herbivores.

Two very obvious anatomical differences between the true herbivores and us omnivorous humans exist: Ruminant stomachs like cattle, sheep and goats, and large cecums like in horses and rabbits. We humans have neither of these. We do not have a four-chambered stomach designed to efficiently digest coarse plant matter like grass, leaves, stems and twigs off of plants. We are monogastrics, simple-stomached animals like pigs, bears, raccoons, dogs, and cats. We do not have a huge cecum designed to digest and ferment forage like horses and rabbits have. (Even ruminants like cows have a functioning cecum!) All we have is a tiny, useless piece of flesh attached to the beginning of our large intestine called the appendix. And the appendix does absolutely nothing for us, except, on occasion, it gives some lucky few of us appendicitis, resulting in having it surgically removed. (Like we needed it in the first place!)

Intestinal Anatomy

Carnivores have shorter intestinal tracts because they don't need so much length to digest the meat they eat. Most of the food they eat is digested and nutrients absorbed in the stomach and the first part of the small intestine (duodenum). Omnivores have a bit longer small intestines because they are also accounting for the plant matter in their diet. Herbivores are longer yet because of the plant-matter diet they consume. We humans tend to be in between the small intestinal length of omnivores and herbivores. And this is because we do tend to eat more plant matter than meat, though we still eat meat (at least most of us do). Many vegans believe that the longer intestinal tract than most omnivores is what sets us apart from "true" omnivores, and is what makes us "herbivores." But looking at the intestinal tract by itself is not looking at the big picture. As I mentioned above, plant matter cannot be efficiently digested in our simple stomachs. It does move slower through our small intestine, but that's because (again) of the many cellulose- and fibrous-tissue that is difficult to get through to extract many nutrients.

Teeth and Use of Tools

The shape and size of our teeth is of little importance compared to the rest of our digestive system. However vegans claim that our flat molars and larger incisors are indicators of the reason why humans should be herbivores and not omnivores nor carnivores. And yet, why do we cook our meat instead of eating it raw? Why have we found that fire is good to make raw meat more tender and easier to chew and invented tools like forks, knives, spears, bows & arrows and then guns? What I see, aside from trying to kill each other, is that these tools were found to help us hunt for meat, cut it up and cook it for us to eat. When the neanderthals were around, they had larger canines than we do now, but that was because they were still living like many omnivorous animals do. They ate meat, as well as plants, but did not (yet) have the inventive skills that Homo sapiens later developed. Soon, however, after the neanderthals did tools get invented to help hunt for big game for the large families that existed. And we evolved from there. Our canines got smaller because we were eating more cooked meat, and didn't need to have the larger fangs that big cats, bears and wolves do. Our molars got flatter because of the cooked-meat diet, as well as the infusion of fruits, nuts and veggies. And since then, we invented agriculture to make getting our food more easier for us, domesticating animals and plants to grow in what are now stalls, pastures and fields.

Health Issues and Today's Societal Laziness

It is a widely-spread claim by vegans and vegetarians alike that meat and dairy products are unhealthy for you. This is only a claim, backed up by falsehoods that have no relevancy whatsoever. They blame meat and dairy for the increased obesity and health problem rates that have come about these past few decades. And what sort of evidence do they bring to the table to back up their statements? The following:

  • Higher rates of obesity and cardiovascular disease
  • Meat and dairy have higher levels of saturated fats, cholestrol, and animal protein
  • Increases blood cholestrol levels, blood pressure, hypertension, type 2 diabetes, and prostate and colon cancer
  • Eating vegetables is better for the environment because it uses far fewer resources and causes less environmental damage than an a meat-based diet. (Covered later)

The REAL Truth from the Claims

Health Issues of Today's Society

Much of the obesity, cardiovascular disease and cholestrol problems we see today is not really linked to animal protein in itself. It is more due to the increase intake of far more unhealthier foods like processed cheese, potatoe chips, candy, cookies, and other foods high in carbohydrates and sugar. Sucrose, a type of sugar that is commonly used in candy and other processed goodies, is far more unhealthier than healthier sugars like fructose, glucose and lactose. Kids who have obesity issues tend to gorge themselves on diets high in carbohydrates and sugar and fast food, not getting enough healthier dairy, fruit, vegetable or meat products every day instead. Also, our portions have doubled in size from the past as well. The size of meat serving is a big problem, as you see in the Big Macs or the Double Cheeseburger. And these burgers, the groud beef used in them, comes from grain-fed cows and corn. The meat you see in your grocery stores are also from grain-fed, intensly managed animals. Grain-fed cattle are unhealthy creatures, and it has reflected that in the health problems in humans from eating grain-fed beef. Essentially, convinient foods are our downfall. Corn has made our foods convinient, since corn is found in virtually everything we eat, except for fruit and vegetables. The fact that today's society mostly comprises of lazy, computer and TV-dwelling people is what initiated modern conveniences, including the fast food and pre-packaged food we eat.

Much of the health problems we also face is als linked to inadequate excersize and physical activity. Computers, television, satellite television, video games, and other electronics are what makes us couch potatoes. Lack of physical activity is never healthy for anybody, and that also reflects on what and how we eat.

Meat isn't the main cause for health problems and cancer in today's population. It's us. A growing population demands more food to be produced sooner, and this is why we are seeing animals being factory farmed like they are, and fruit and vegetables being produced in mass quantities. It's the fact of Quantity over Quality. And that is also our downfall.

Health Issues of a Vegan Diet

A vegan diet may provide more servings of fruit and vegetables every day, but it also lacks in serveral important nutrients that are found in animal products: iron, vitamin B12, and omega 3 fatty acids. All nutrients are vital to human health and nutrition, and if not supplemented in a vegan diet, will lead to more problems than a person who follows a healthy, balanced diet of fruit, vegetables, whole grains, and meat and dairy products.

Vitamin B12 is not found in any plant-based meal including beans and soybeans. Vitamin B12 is found in animal products like eggs, fish, dairy and beef products. In pregnant women, it is essential for the healthy development of fetal neurological system, and also neurological health in people themselves. Unreliable sources for V B12 include Tempeh, seaweed, spirulina, organic produce, soil on unwashed vegetables, and intestinal bacteria.

Iron deficiencies are also common in vegan diets. Iron tends to be less well-absorbed in vegetarian diets than omnivorous diets, and those who exclude all animal-based sources from their diets will need twice as much iron to supplement than non-vegans. Iron deficiencies is a much bigger problem in women than men because of the menstral cycles, lactation and gestational periods they often go through.

Omega 3 fatty acids are also low in vegan diets. This is a much bigger issue for pregnant and breast-feeding women on a strict vegan diet, as a deficiency of this leads to lower birth weights and eye-sight problems in children.


Overall, there is good and bad to each diet we follow. However, I would like to say this: most vegans are partly right about the meat we eat. But I only say partly because many vegans tend to generalize that all meat as bad. But it isn't, especially if we loosen our grip on grain-fed meat and dairy products and instead, buy grass-fed beef and dairy products instead. Grass-fed and naturally raised meat products are, by far, healthier than the TV-dinner diet we are so fixated on. Plus, if we ate less carbohydrate and starchy foods like pizza, potatoe chips and hamburgers, and more fruits and vegetables, we wouldn't have as much problems. And for heaven's sake, get off your butt and go out for a walk or bike ride every day! Or go walk your dog for an hour! You'll certainly feel better afterwards!


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    • WildRoseBeef profile image

      WildRoseBeef 3 years ago from Alberta, Canada

      It does, yes, but to a lesser extent. But you're still right that I made an error in that comment. The appendix also plays an important role in the lymphatic system.

      Not sure when I'm going to change it, but remind me again if I haven't changed it for a while since now.



    • profile image

      Nate 3 years ago

      There is an error in your post:

      "And the appendix does absolutely nothing for us, except, on occasion, it gives some lucky few of us appendicitis, resulting in having it surgically removed. (Like we needed it in the first place!)"

      The appendix plays an important role for the beneficial bacteria living in the human gut. serves a purpose

    • WildRoseBeef profile image

      WildRoseBeef 4 years ago from Alberta, Canada

      LOL, thanks Richard, for that. Even though I'm a supporter for eating meat, I'm much more of a supporter for eating more vegetables than grains and having a little meat on the side. I'm not big on the dairy either. :)

    • RichardSpeaks profile image

      Richard Kent Matthews 4 years ago from Portland, OR Metro Area

      As a vegetarian, not vegan, I have found that a few eggs and cheese make it easier to do without meat, fish, or foul. I tried the vegan route, but could not maintain it for too long. After the initial guilt, I got on with my life. I do buy organic, free range eggs and organic cheese. But little else in the form of dairy or animal products. No yogurt or ice cream, milk or whipped cream. Well, sometimes the whipped cream.. ha

    • WildRoseBeef profile image

      WildRoseBeef 4 years ago from Alberta, Canada

      AJ, thanks for your comment, but I think you yourself have your information wrong. B12 is produced by bacteria, not any plants themselves (no doubt you got that off of several pro-vegan sites), and eating dirt often isn't near enough for a human to get the b12 they need. As far as the grazers are concerned, they don't get their Vitamin B12 from the grass, they get it from the microbes that live in their rumen or digestive tract. So no, no form of B12 is found in any plant sources. If it was, it was as an analogue, not a true B12 form which can be used by us humans. Gut bacteria in our bodies can produce B12, but it is unusable to us because it is too far along the digestive tract. Therefore, B12 must be supplemented in fortified foods or vitamin-pill form, not solely and dumbly assumed to be found on all plants.

      Many vegans run into serious b12 deficiencies--in the form of anemia, which is commonly known as an iron deficiency--because of that very wrong belief which you voiced above. Many, many vegans do not have the opportunity to eat their vegetables "fresh from the ground," as many don't have a garden. Rather they get their produce from the grocery store which has vegetables that have been washed already before it hits the shelves. And yes, iron is and often will be lacking. Iron from plants is unusable unless a source of Vitamin C is taken along with it. Otherwise, it just gets excreted, and results in a serious deficiency unless supplemented in pill form. Or the person goes back to consuming meat and eggs plus plenty of plants. Omega 3 may not be a big issue, but iron, b12, and protein is.

      I've heard much different about vegans getting "sick less" or "living longer." You cannot be a vegan your whole life because you will get sick from deficiencies in the various nutrients described above, and even fat from an excess of carbohydrates, something which makes up most of the vegan diet, and which has found to be more harmful than meat. People are more fat because of the high carbohydrate diets, not the meat. There are also no reputable, viable studies that show that vegans live longer than "meat-eaters" = omnivores. If there were, they would be seriously flawed to be not worth taking into account.

      I would suggest the same to you to do your own research and check your facts--as I have already done with my article above--before claiming that much of the information I "reported" above is "seemingly incorrect." It's highly advisable to check your facts to non-biased sources, instead of biased, pro-vegan sources.

    • profile image

      AJ 4 years ago

      Sorry but a vegan diet does not lack iron, omega 3 fatty acids (can't believe you said this one) and B12. B12 is in dirt, the animals that eat grass absorb their b12 from this source, that is how you get your b12 from meat. Vegans who eat their vegetables fresh from the ground (and not over wash them) get their b12 the same way as these animals. B12 has also been found in other plant food sources, so please check your facts before reporting information that is seemingly incorrect. Anyway vegans must be doing something right if they live longer than meat-eaters, and get sick less. ;)

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      Evan T 5 years ago

      I think we are ment to eat bugs there protein.. we cant run very fast were also small good luck.. they seem to enjoy bugs in the middle east comeone this is 2012

    • RichardSpeaks profile image

      Richard Kent Matthews 5 years ago from Portland, OR Metro Area

      OK. Clear.

    • WildRoseBeef profile image

      WildRoseBeef 5 years ago from Alberta, Canada

      For your first question, that's not the point. We've found fire and developed a thing called weapons to do all that for us. And it's all because of a thing called civilization and society that allows a select few to make food for others. Your second question thus leads me to challenge you with this: If we're going to be eating, perhaps we shouldn't let others make our food for us.

      I have actually taken a trip to the slaughterhouse, seen near about the whole process and it hasn't changed my mind about eating meat. I don't eat as much meat as I have in the past, but that's more due to health issues rather than ethical issues. Some people are a lot more sensitive and softer than others. I tend to be one of those "other" people. :)


    • RichardSpeaks profile image

      Richard Kent Matthews 5 years ago from Portland, OR Metro Area

      A trip to the slaughterhouse might change a mind or two. Plus, if in the natural state we are omnivores, why can we not successfully chase down our animal food, rip its throat out, eat blood, entrails, as well as muscle tissue, without resorting to the need to cook it? If we're going to be meat eaters, perhaps we shouldn't let others do our killing for us. See, most vegans are not vegans because of the health or stomach or protein issues but because of the ethical issues. Slaughterhouses are houses of torture and inhumane treatment.

    • WildRoseBeef profile image

      WildRoseBeef 5 years ago from Alberta, Canada

      That's fine, Brenzel, your comments are welcome and it helps to have someone like you to get into the more specifics of such things as jaw and teeth anatomy and how things have evolved from the age of the Neanderthals to the age of the Modern Human.

      I think the larger canids statement with the Neandrethals was probably my own speculation, though if it was cited then it would've been either from a National Geographic magazine or somewhere else I read about it that I've long forgotten. :)

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      t.brenzel 5 years ago

      I'm also curious if you have some citation about the neanderthals larger canines vs. ours evolving smaller and flatter due to cooking our meat . . . or is that your own speculation?

      Even if their canines were more pronounced, that's a far cry from comparing them to the spine-piercing, grabbing function of a big cat or even wolf to taking down prey.

      The mouth size vs. how wide the jaw opens is also an important part of predation--think how wide a wolf or dog can open to clamp down on something, sort of wrap around a whole limb of a larger animal . . . You really have to account for that as well.

      Sorry to go on,:), I'm just fascinated by the specializations of mammal teeth lately! Recently read how teeth in animals started out as all conical --very generic (like alligators, reptiles) and then started to specialize for different mammals as their diets specialized. I believe I was listening to Science Friday on NPR last week, when a fellow talking said the key to human success was that we were such good generalists, not too specific about what we eat or temperatures where we live . . .. whereas some animals are very dependent on (like a koala) their niche food.

    • WildRoseBeef profile image

      WildRoseBeef 5 years ago from Alberta, Canada

      Thanks for your input, Julia and T.Brenzel.

    • profile image

      t.brenzel 5 years ago

      Yeah, I'm with Julie--it's a gross over-simplification to start with a presumption that all herbivores can process any and all plant matter with the same efficiency. Leaving humans aside, there are plenty of plant only eaters that couldn't digest grasses the way horses and cows can . . . . such as a lemur, koala, fruit bat or manatee . . . yet that would not scientifically prove they aren't herbivores .

      Even horses and cows have somewhat different processes for digesting grasses.

      We humans get so caught up in classification and making "definitive" labels--nature doesn't. Obviously humans have been omnivorous for quite some time, regardless of what our physiology looks best designed for.

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      Julle 6 years ago

      You talk about greens, cows, stomachs... but what about fruit? Humans are really like apes. Apes are 99% fruitarians. Today there is thousands or fruitarian people and it looks like they thrive and has magnificient fitness and halth.

    • WildRoseBeef profile image

      WildRoseBeef 7 years ago from Alberta, Canada

      Hi NT,

      Thanks for the comment. As a matter of fact I own both books. :)

      As for your question, no. Cows are able to efficiently digest grass with their 4-chambered stomachs without any adverse effects like constipation or anything like that. They do well on fibre-rich roughage, so long it is not too woody, like the bark off of trees. However, if the grass is really poor quality, then there may be some problems, but normally grass is good-enough quality that constipation or gut-impaction won't happen.

      Zoey, thanks for your comment as well. And thank you for the additional info, I kinda figured I missed something, so thank you for that. :)

    • nettraveller profile image

      nettraveller 7 years ago from USA

      Yes, a very good hub! Have you read Michael Pollan's "An Omnivore's Dilemma" and Temple Grandin's "Animal Translation" ? Both deal with your favorite subject, in different ways. If you use Amazon, you could even offer them to your readers here.

      Since cows can digest plant tissues so much more effectively (thanks to their intestinal or gastric guests), could they ever get constipated on grass, or does it still provide enough indigestible fiber and roughage?

    • profile image

      Zoey 7 years ago

      Hi - excellent articles! I work in animal science and something that I may add to this discussion is fact about conjugated linoleic acids (CLA). They have many health-benefits including prevention of cancer and obesity, and CLA are only found in significant quantities in ruminant meat and milk.