Small intestines compared to body length

[Beuford]

So some of you might have seen a comparitive anatomy of humans to herbivores, omnivores and carnviores?

Do you think it is correct when it says humans small intestines are 10-11x our body length?

At first I thought, well I'm 1.8m tall and my intestines are 6-7m, that should come up in the 3-4x body length. Then I worked out body length didn't include legs or head, so I measured the length from my neck to the top of my legs and I got 60cm.

60cm x 10 = 6m
60cm x 11 = 6.6m

So, the 10-11x body length for our small intestines is true for me.

If you're convinced a diet high in meat is good, and that you don't have herbivore length intestines, why don't you measure your body length? Or, tell me why herbivore length intestines don't matter, I'm interested to know.

[liamona]

Originally Posted by Beuford

If you're convinced a diet high in meat is good, and that you don't have herbivore length intestines, why don't you measure your body length? Or, tell me why herbivore length intestines don't matter, I'm interested to know.

I think the main reason it doesn't matter is because digestion depends on how much good bacteria you have in your gut and how much fat you eat.

Konstantin Monastyrsky, the author of Fiber Menace has a ton of information on digestion and poop on his website.

This is basic information that is available in any college handbook on Human Physiology, but Monastyrsky breaks it down into layman's terms:

"Protein from meat, fish, fowl, dairy, seafood and plants digests completely and is absorbed into blood as amino acids. So there’s no protein in normal stools, except burned meat."

"Close to 95% of all consumed fat is absorbed in the small intestine."

"Q. Is it true that animal fat causes constipation?

No, it isn’t. In fact, it’s the complete opposite: low-fat diets cause constipation while excess fat causes diarrhea. Anyone who tells you otherwise needs a mental check considering that vegetable oils have been used as potent laxatives for millennia. Chemically, flax, olive or castor oils are fat just as much as lard, tallow, or butter — except they are liquid and easier to swallow in one large dose."

"Finally, why do low-fat diets contribute to constipation? Dietary fat stimulates the release of bile from the gallbladder, which, in turn, stimulates the gastrocolic reflex. This in turn stimulates peristaltic mass movement, which, in turn, stimulates defecation. No fat in the diet = not enough bile in the system to get the ball rolling"

“Energy-rich meals with a high fat content increase motility [propulsion of stools]; carbohydrates and proteins have no effect.” (Source: Human Physiology [10])"

From: Gut Sense: Restoring Natural Bowel Movements

This page talks about the importance of having enough good bacteria in the gut:

Gut Sense: Restoring Intestinal Flora

[agnostic]

Originally Posted by Beuford

So some of you might have seen a comparitive anatomy of humans to herbivores, omnivores and carnviores?

Do you think it is correct when it says humans small intestines are 10-11x our body length?

When we are dead, yes. It's much shorter while we are alive. I'll give you a quote from a corresponding paper once I have access to it again.

Originally Posted by Beuford

At first I thought, well I'm 1.8m tall and my intestines are 6-7m, that should come up in the 3-4x body length. Then I worked out body length didn't include legs or head, so I measured the length from my neck to the top of my legs and I got 60cm.

60cm x 10 = 6m
60cm x 11 = 6.6m

So, the 10-11x body length for our small intestines is true for me.

If you're convinced a diet high in meat is good, and that you don't have herbivore length intestines, why don't you measure your body length? Or, tell me why herbivore length intestines don't matter, I'm interested to know.

I don't know why they should matter more than all the other parts of the human digestive system. Walter Voegtlin, a gastroenterologist, wrote the book "The Stone Age Diet", which you can read in full here.
It compares the human digestive system to both sheep and dog and comes to the conclusion that man's digestion is functionally identical to that of a dog and fundamentally different from that of a sheep. You can find the table that sums it up here.

Even if we take your 1:11 ratio (I haven't found any source which says how these numbers are actually obtained, so I can't say if it's 1:3 or 1:11), man is still closer to the dog at 1:6 than he is to the sheep at 1:25.
We don't ruminate, which is vital to a sheep since it doesn't get access to the plant's nutrients without it. We also have a small stomach which - unlike the sheep's and very much like the dog's- empties within a few hours and actually remains empty for some time, which is never the case for a herbivore like a sheep. If I counted correctly, Voegtlin lists 41 factors that make man's digestive system similar to a carnivore and different from a herbivore. Why is the intestine length factor, which points more into the carnivore direction, too, more important than the others?

[Beuford]

Yes some herbivores have very very long intestines, but carnivores and omnivores have much shorter, half the length of a human. There are herbivores that have intestine lengths 10x their body. We are clearly not grass eating grazing animals so of course we are not like a sheep. My teeth are nothing like a dogs. I've seen a dog with it's mouth open, all of his teeth were sharp and his tongue was big and rough.

[Writertype]

Originally Posted by Beuford

My teeth are nothing like a dogs. I've seen a dog with it's mouth open, all of his teeth were sharp and his tongue was big and rough.

But your eyes are like a dog's, or a cat's, or a bird of prey's. They are forward-facing and binocular rather than widely spaced to survey for the movements of predators. That allows for excellent depth perception, which carnivores need for chasing down prey.

You are right that there seem to be many similarities between our bodies and the bodies of herbivores. Others are also right when they say that there seem to be many similarities between our bodies and the bodies of carnivores.

This could reasonably lead you to the shocking conclusion that (drumroll, please) we are adapted for both eating vegetation and eating meat!

[BoBoGuy]

Originally Posted by Writertype

This could reasonably lead you to the shocking conclusion that (drumroll, please) we are adapted for both eating vegetation and eating meat!

All relevant anatomical traits suggest that humans are classical examples of omnivores. There is simply no basis in anatomy or physiology for the assumption that humans are pre-adapted to a purely vegetarian diet. For that reason, the best arguments in support of a meat-free diet will remain to be ecological, ethical, and health concerns.

Our biological make up is between that of vegetarian animals like cows and that of purely meat eating species like cats and dogs. In other words: we get to choose.

Bo

[Beuford]

Originally Posted by Writertype

This could reasonably lead you to the shocking conclusion that (drumroll, please) we are adapted for both eating vegetation and eating meat!

I find a mountain of evidence suggesting we are herbivores and a small pile suggesting otherwise. This leads me to the conclusion that our diets should be at least 95%+ plant, with the last 5% being insects, or an occasional small animal in the case of survival.

[scorpio1980]

Wow, 97% of the worlds population is wrong? If we are naturally herbavoire it sure is crazy that we can eat an omnivoire diet, and live to a very old age. Feed a cat nothing but beans, fruit, and veggies see how long he lives. Or take a cow, and feed it a diet of meat, and fat see how healthy he is. In both cases the animals will get sick, and die, because they are not adapted to that particular diet. Humans on the other hand can not only survive, but we thrive, and have lived as omnivoires since the beggining. Since we can thrive off eigther food than that throws your herbavoire nonsense out the window. If we were herbavoires a diet of animal foods would make us sick very quickly just like any other herbavoire fed meat. Why do you not believe the countless years of studies that prove we are omnivoires? Meat is not the culprit, man made chemicals are.

[Beuford]

97% is for the US, for the whole world it would probably be closer to 50%, or somewhere inbetween. I have not seen countless studies proving we are omnivores and all the ones I have seen don't seem to prove anything. I'm yet to find an anatomy comparison of humans to omnivores which shows we are clearly omnivores. Omnivores do not suffer strokes and heart attacks from eating too much cholesterol and saturated fat, even if they eat factory farmed non organic meat.

[Beuford]

Originally Posted by scorpio1980

Humans on the other hand can not only survive, but we thrive, and have lived as omnivoires since the beggining.

Except that primates, who we evolved from and share similiar anatomy with, are at least 95% herbivores.

[Aleksander Krstic]

Originally Posted by scorpio1980

Wow, 97% of the worlds population is wrong?

Precisely.

Feed a cat nothing but beans, fruit, and veggies see how long he lives. Or take a cow, and feed it a diet of meat, and fat see how healthy he is. In both cases the animals will get sick, and die, because they are not adapted to that particular diet.

Have you fed such an animal before?

If we were herbavoires a diet of animal foods would make us sick very quickly just like any other herbavoire fed meat.

They DO make us sick, just not to the extent where we would be "really sick", but rather it makes us unhealthy.

Why do you not believe the countless years of studies that prove we are omnivoires?

Countless years of Illuminati-type marketing and lies known by a handful of men.

Meat is not the culprit, man made chemicals are.

An excuse.

[stripysweatergirl]

Why do so many vegans simply ignore the fact that some people feel better when they eat a mixed diet of meat and vegetation, than simply vegetation alone?

I have tried being a vegetarian and vegan and simply feel more energetic and healthy when I include some meat in my diet. Can you honestly tell me I'm not adapted to eat some meat when this is the case?

I think vegans tend to set up strawman arguments a lot. "Oh you eat meat? Well if you ate nothing but meat you'd get ill pretty quickly!" But the truth is that very few, if any, meat eaters ever advocate eating an entirely meat diet. We do not deny the health benefits of vegetation, why do you continue to deny the health benefits I receive from eating some meat in my diet?

[Beuford]

Some people also feel pretty good after eating chocolates, mcdonalds, smoking cigarettes etc. That doesn't make it healthy.

Some people also conclude a vegetarian diet doesn't work for them because it was filled with foods like white pasta and candy.

I can adapt to drinking 3 cups of coffee each morning and I'd feel pretty bad if I didn't get any coffee, but that doesn't make it healthy and it doesn't mean I've naturally evolved to drinking coffee.

[Joeschmoe]

Originally Posted by Writertype

But your eyes are like a dog's, or a cat's, or a bird of prey's. They are forward-facing and binocular rather than widely spaced to survey for the movements of predators. That allows for excellent depth perception, which carnivores need for chasing down prey.

Pandas
Koalas
Sloths
Many Monkeys, Lemurs, Apes
And others

Sometimes developing forward facing eyes is a result of navigating a complex 3-D environment and not hunting prey. But again the whole argument falls flat. It doesn't really matter what we evolved to eat, it matters what makes us the healthiest. If i found out tomorrow that eating a pound of bacon a day made me healthier, I'd find a local farmer to buy my bacon from and thank the pigs for my longer life. I don't see any scientific evidence that meat consumption is a healthier option that a mostly vegan diet.

[Beuford]

Originally Posted by Writertype

That allows for excellent depth perception, which carnivores need for chasing down prey.

I'll add that I'm too slow to do that. I run like a herbivore, slow and long distance. Even the top sprinters are slow compared to omnivores and carnivores. Perspiring helps. Herbivores perspire through their skin pores. Omnivores perspire through their tongue, not through their skin.

[stripysweatergirl]

Originally Posted by Beuford

Some people also feel pretty good after eating chocolates, mcdonalds, smoking cigarettes etc. That doesn't make it healthy.

Some people also conclude a vegetarian diet doesn't work for them because it was filled with foods like white pasta and candy.

I can adapt to drinking 3 cups of coffee each morning and I'd feel pretty bad if I didn't get any coffee, but that doesn't make it healthy and it doesn't mean I've naturally evolved to drinking coffee.

Well, I don't know about some people, but I eat very healthily, and, therefore, when I tried being vegetarian and vegan, I tried many combinations of foods- high carb, low carb, no carb, always with lots of fruit and vegetables- which I still now eat in a high proportion alongside meat.

If you didn't have your coffee, you would get withdrawal symptoms and then feel better. That didn't happen when I removed meat from my diet.

You cannot possibly argue with someone over their own diet which they have thoroughly empirically investigated to find the one that makes them feel the best. I'm not telling you to eat meat because maybe you don't feel good when you eat it, only pointing out that there is not, and can never be, one rule for everyone, particularly when it comes to diet.

[Parthon]

If you might have noticed, there's a huge difference between primates and herd animals. Those animals that eat grass need a large or multiple stomachs to break down plant fibers, but those animals that eat vegetables and fruits as a majority of their diet tend to have smaller stomachs and shorter intestines.

As anatomy goes, our digestive system would be closer to the systems in pigs, bears, primates and other omnivore and fruit/vegetable eating animals.

Has anyone found any research to compare us to those kinds of animals rather than primarily grazing herbivores or meat heavy carnivores?

Truthfully, there is no one gobal diet that will suit everyone. Our main strength as humans are our diversity, being able to live in the coldest climate and the hottest, go everywhere and do everything. No other animal can boast that kind of flexibility, so we shouldn't expect rgidity in our diets. Eat what makes you the most healthy, and what makes the planet the most healthy.

[garentee]

The reason why pigs are used so heavily in medical school is because we are very similar to them in our make up.. I have no studies to suggest this is actually true, but I have heard this on more than one occasion and do remember hearing it as the main reason why we disected a fetal pig in Biology class in High school. I have seen the whole pig intact and broken down and we are pretty darn similar....That does not keep me from eating them by the way....

[agnostic]

Whew! What a Thread!!

Originally Posted by Beuford

I find a mountain of evidence suggesting we are herbivores and a small pile suggesting otherwise. This leads me to the conclusion that our diets should be at least 95%+ plant, with the last 5% being insects, or an occasional small animal in the case of survival.

Could you point me to that mountain? I'd really like to read some of the stuff you would reference for statements like this, because it clearly goes against what I have read. What you find is usually based on what you are looking for. So I'd like to know more about where your point of view comes from.

I really doubt that any primate would only eat "an occasional small animal in the case of survival".

There are severe limits to comparing us to monkeys. We are, after all, another animal. We evolved into the big-brained primates we are probably because of the introduction of high-caloric animal foods. Which pressure actually caused the evolution may be open as there are many options. But the fuel for it is pretty clear among anthropologists: meat.
It allowed us to have a smaller gut and thus develop more similarly energetically expensive brain tissue. It's called the Expensive Tissue Hypothesis. You can read a very good explaination and get a link to the original paper here.

[Joeschmoe]

Originally Posted by agnostic

Whew! What a Thread!!



Could you point me to that mountain? I'd really like to read some of the stuff you would reference for statements like this, because it clearly goes against what I have read. What you find is usually based on what you are looking for. So I'd like to know more about where your point of view comes from.

I really doubt that any primate would only eat "an occasional small animal in the case of survival".

There are severe limits to comparing us to monkeys. We are, after all, another animal. We evolved into the big-brained primates we are probably because of the introduction of high-caloric animal foods. Which pressure actually caused the evolution may be open as there are many options. But the fuel for it is pretty clear among anthropologists: meat.
It allowed us to have a smaller gut and thus develop more similarly energetically expensive brain tissue. It's called the Expensive Tissue Hypothesis. You can read a very good explaination and get a link to the original paper here.

There is actually new data out that it might have been more about the tubers than the meat. Tubers were everywhere and a relatively under-used resource.

Diet and the evolution of human amylase gene copy number variation

Again, the argument is pretty pointless. There is plenty of evidence now that eating excess meat is harmful to health, no matter what we evolved eating.

[Fullcrum]

People who argue that humans do not have the "sharp claws, fangs, etc." of a carnivore are using a fallacious argument. Humans and our ancestors have used tools since the beginning of our existence. Even chimps use tools. Just because they need tools to eat grubs and insects does not mean they are not adapted to eat them. They don't need "stick tongues, burrowing claws to get into anthills, fast reflexes, long tongues" or any other traits classically associated with insectivorism. They simply have tools and primitive culture (learned behaviors passed through generations) that keeps the consumption of insects alive. Chimps eat meat, as seen in the video above. They lack fangs, biting teeth, etc., but they still eat meat.

Similarly, anthropological evidence demonstrates that humans ate more meat as we became more like our current form. Cut marks from stone tools in marrow bones show that we were scavengers and could eat what other carnivores often could not, the rich and nutritious marrow. Spears later allowed us to hunt animals.

Interestingly, the spears of our cousins the Neaderthals were designed for jabbing, not throwing, while ours could be thrown from a distance. This may have made us better hunters than them.

Also, consider primitive cultures.

Some exist that eat pure meat or almost pure meat diets. Think of the Chukchi of Russia or the Inuit of Alaska and Northern Canada. The most vegetation the latter ever got before the arrival of explorers and civilization were cranberries.

This doesn't make modern meat the healthiest food out there, but it does show we evolved with it.

[BoBoGuy]

Human ancestors were never in a position to be vegan. Paleobiology and paleobotany tells us that--where humans evolved--there did not exist the edible plant biomass in sufficient quantity to sustain human populations. There is no known combination of plants available in the regions and climates where humans evolved that would allow enough humans to eat year round to maintain viable reproducing groups. You'll notice that of the modern plants edible by humans, that all are seasonal.

[Writertype]

More arguments below for 'meat eating features' of human anatomy, since some seem to claim they don't exist. Again, the evidence is mixed. Our anatomy suggests that we are omnivores.

From http://www.rense.com/general20/meant.htm:

"...several of our physiological features "clearly indicate a design" for eating meat, including "our stomach's production of hydrochloric acid, something not found in herbivores. Furthermore, the human pancreas manufactures a full range of digestive enzymes to handle a wide variety of foods, both animal and vegetable.

"While humans may have longer intestines than animal carnivores, they are not as long as herbivores'; nor do we possess multiple stomachs like many herbivores, nor do we chew cud," the magazine adds. "Our physiology definitely indicates a mixed feeder."

If people were designed to be strict vegetarians, McArdle expects we would have a specialized colon, specialized teeth and a stomach that doesn't have a generalized pH-all the better to handle roughage. Tom Billings, a vegetarian for three decades and site editor of BeyondVeg.com, believes humans are natural omnivores. Helping prove it, he says, is the fact that people have a low synthesis rate of the fatty acid DHA and of taurine, suggesting our early ancestors relied on animal foods to get these nutrients. Vitamin B-12, also, isn't reliably found in plants. That, Billings says, left "animal foods as the reliable source during evolution."

History argues in favor of the omnivore argument, considering that humans have eaten meat for 2.5 million years or more, according to fossil evidence."

[agnostic]

Originally Posted by Joeschmoe

There is actually new data out that it might have been more about the tubers than the meat. Tubers were everywhere and a relatively under-used resource.

Diet and the evolution of human amylase gene copy number variation

Again, the argument is pretty pointless. There is plenty of evidence now that eating excess meat is harmful to health, no matter what we evolved eating.

Thanks a lot for the link. It may well be that tubers had an important part in the human diet, too. We certainly can ingest starches when properly cooked. However, the negative effects of lectins from potatoes on humans does shed some doubt on this theory.

I would really like to see any evidence that eating excess meat is harmful to health. Most of it is about saturated fat and cholesterol being bad, which is nonsense. The rest is about the way we raise meat, which actually sucks, but can be avoided by eating organic grass-fed beef.

But I'm willing to learn. You found one cool link, maybe you have another one.

[ginkgo]

Originally Posted by Writertype

But your eyes are like a dog's, or a cat's, or a bird of prey's. They are forward-facing and binocular rather than widely spaced to survey for the movements of predators. That allows for excellent depth perception, which carnivores need for chasing down prey.

You are right that there seem to be many similarities between our bodies and the bodies of herbivores. Others are also right when they say that there seem to be many similarities between our bodies and the bodies of carnivores.

This could reasonably lead you to the shocking conclusion that (drumroll, please) we are adapted for both eating vegetation and eating meat!

So why do animals have eyes on the sides of their heads.

It is because other animals are looking to eat them! Otherwise it is bettor to have eyes in the front of the head. Why? Who says so? Why do you say that? Because with 2 eyes you can see in 3-D. With eyes on the side of the head, you cannot see in 3-D.

So we have 2 eyes in front so we can see 3-D movies. Also in the U.S., you cannot drive if you only have one eye that sees. Is this cause they do not like one-eyed people? No! It is cause they cannot see in 3 dimensions and gauge distances. Everything to them is the same distance.

Say you want to find where a radio signal is coming from. One tracker can tell you the line that it is coming from (the exact direction). But it cannot tell you where on the line it is coming from. With a second tracker you have a second line of where it is coming from. Then you figure out where the 2 lines cross and you know the exact point that it is coming from.

This is the first thing that you learn in geometry or gee, I'm a tree. Why do we have 2 ears? For the same reason, to gauge where the sound is coming from. Then why 2 nostrils? Since it is normal for one to be clogged while dispelling mucus.

Many apes and monkeys eat no meat but they have eyes in the front of the head. Other animals do not go hunting for them since gorillas are king of the jungle. That is where they got the idea of King Kong and Mighty Joe Young.

Also they are like ducks. Ducks stick together. You mess with one duck and you have to fight them all. Now primates are the most evolved of the animals.

Seeing in color has nothing to do with eating meat or not, but most animals cannot see in color, but humans can. Why? Because it is a better way to see and so we can watch color TV and have color monitors. And also so this forum can have colored text. I apologize for this if you are color blind or have only one eye. No offense intended.

Since the human is at the apex of evolution, he has the ability to live off of many varied foods. He can eat greens like herbivores. He can eat meat like lions. He can eat other humans (cannibalism) unlike many meat-eating animals but like fish-- guppies. He can eat rats like snakes. He can eat bugs like frogs and lizards do. He can eat algae like the fish do. He can eat worms like birds do and man can fly in the air like a bird. This makes him better at survival.