Are we really designed for eating meat? That is the question I will try and answer based on my own research that takes a few key points into consideration out of numerous other reasons. I will go through anatomy, biology, physiology, B12, Cholesterol, Vitamin C, IGF-1, TMAO, longevity, food consumption statistics, food consumption history and the development of the brain. I will provide sources for everything I say.
Now before I start I think this basic question needs to be asked. If we were designed to eat meat, how come there are hundreds of thousands and even millions of people that are strict plant based eaters who are healthy and thriving? If we truly are designed to eat meat then there would not exist that many healthy strict plant based eaters. Also long life does not necessarily means healthy life since there are multiple reasons to why people live long time and not just diet like living standard and access to clean water and healthcare but it sure is an indicator if looked at from the proper point of view which broad population studies offers.
Now just because we have the ability to consume something does not automatically mean we should or that it's designed for us. There are people who eat sand but that doesn't automatically mean we should. There are people who eaten metal and glass in the amounts of a whole airplane but that doesn't automatically mean we should. There are people who eaten paper but that doesn't automatically mean we should. So just because there are people who eaten meat their whole lives and throughout our history does not automatically mean we should.
"The man addicted to eating SAND: Rare condition means Indian labourer consumes a plate of gravel a day"
http://www.dailymail.co.uk/health/article-3438514/The-man-addicted-eating-SAND-Rare-condition-means-Indian-labourer-consumes-plate-gravel-day.html
"Woman who eats 1KG of SAND every day claims to be perfectly healthy"
https://www.mirror.co.uk/news/weird-news/woman-who-eats-1kg-sand-5696822
"Weird world records: bizarre entries in the Guinness Book of World Records"
https://www.telegraph.co.uk/news/picturegalleries/howaboutthat/2976278/Weird-world-records-bizarre-entries-in-the-Guinness-Book-of-World-Records.html?image=3
We need to look at our anatomy and psychology and all that says we are designed for something else and not meat.
"Are We Meant To Eat Meat, By Author: Milton Mills, M.D"
The fact that we do not produce our own Vitamin C tells us that we are extremely connected to fruits, berries and vegetables. According to one source, the gene for producing Vitamin C stretches back 60 million years which is still inactive. So for 60 million years we have not produced our own Vitamin C which requires the consumption of fruits, berries and vegetables in order to survive or we may die from scurvy.
"Vitamin C Production in Goats vs Humans"
The requirement of ascorbic acid is a common property among living organisms. It has long been considered that all animals with the exceptions of guinea pigs, monkeys, and humans can produce their own vitamin C. Scientist have extensively studied the human genome and identified the defective gene for the synthesis of the active enzyme protein, L-gulonolactone oxidase or GLO (Stone 1979). This mutation is said to have occurred some 60 million years ago. The absence of GLO in the human liver blocks the conversion of glucose into ascorbic acid leading to an illness known as Scurvy (Inborn error of carbohydrate metabolism).
https://blog.livonlabs.com/goat-vitamin-c-production/
A quick search for how long we eaten meat suggests 2.5 million years. That means that we eaten anything but meat for 57.5 million years which clearly shows that we are adapted to a non-meat diet and are yet to adapt to eating meat since even low levels of animal protein increases the production of Insulin-like Growth Factor 1(IGF-1) that increases the risk of cancer which shouldn't happen if we are truly designed for the consumption of meat.
"IGF-1"
Studies have found no association between total protein intake and IGF-1 levels. Doesn’t that just go against everything I just said? Ah, but these studies didn’t take into account animal versus plant protein.
In this study of meat-eaters, vegetarians, and vegans, they found no significant difference in IGF levels between people eating lots of protein, compared to people eating less protein. But before ditching the theory that excessive protein intake boosts the levels of IGF-1, they decided to break it down into animal protein versus plant protein.
Higher IGF-1 levels were just associated with animal protein intake. In fact, the plant protein seemed to decrease IGF-1 levels. So, no wonder there was no net effect of total protein intake. Animal protein appears to send a much different signal to our livers than most plant proteins. So even those vegans eating the same amount of protein as meat-eaters still had lower levels of the cancer-promoting hormone, IGF-1.
https://nutritionfacts.org/topics/igf-1/
https://nutritionfacts.org/video/protein-intake-and-igf-1-production/
""Evolving to Eat Mush": How Meat Changed Our Bodies"
Carnivorous humans go back a long way. Stone tools for butchering meat, and animal bones with corresponding cut marks on them, first appear in the fossil record about 2.5 million years ago.
How Did Meat-Eating Start?
Some early humans may have started eating meat as a way to survive within their own ecological niche.
Competition from other species may be a key element of natural selection that has molded anatomy and behavior, according to Craig B. Stanford, an ecologist at the University of Southern California (USC)."
https://news.nationalgeographic.com/news/2005/02/0218_050218_human_diet.html
Exactly. Meat eating may have started as a survival thing or in combination with competition or who knows and stuck with us ever since just like there are cannibals that still lives. Thing is that we do not need it since 57.5 million years of history clearly shows that we survived without it. Can't get any more obvious than that and no our bodies does not require meat and no B12 is not an argument for meat since neither plants or animals produce B12 but instead are produced by bacteria.
"Vitamin B12: All Your Questions Answered "
In the past, vitamin B12 from bacteria was also naturally and more reliably present in plant foods. Today, however, with modern hygienic practices more effectively cleaning and sanitizing produce, along with soil being exposed to more antibiotics and pesticides, most plant foods are no longer reliable sources of this bacterial product.
https://www.forksoverknives.com/vitamin-b12-questions-answered-2/#gs.zaR_Bxc
According to one source then the Americans have increased their consumption of meat 45% since the 1950's and what has that given them in return by an ever increasing curve? Obesity, heart disease, stroke, Alzheimer, arthritis, diabetes etc.
"American Food Consumption Statistics (Infographic)"
How does this compare to what we were eating in the 1950s?
In the 1950s, the meat and poultry consumed per person on average was 138 lbs a year, which means that meat consumption has increased by around 45 percent over the past 60 years. Cheese consumption in the 1950s was only around 7.7 lbs, while today, Americans consume around 30 lbs of cheese a year. What’s even more startling is that in the 1950s Americans consumed no high fructose corn syrup, but we now consume around 42 lbs on average on an annual basis.
It should come as no surprise to anyone that in the 1950s, only 9.7 percent of American adults were considered to be clinically obese, but today, the United States leads the world with an obesity rate of over 30 percent. Moreover, despite being the richest country in the world, Americans are the least healthy people among the world’s developed nations.
According to the National Institute of Health 80-90 percent of all degenerative diseases (arthritis, Alzheimer’s, cancer, heart disease, diabetes, etc.) are due to environment and lifestyle and are PREVENTABLE. If we want to reverse this trend, a great place to start would be to work on changing some of the statistics below by cutting back on our consumption of disease promoting animal-derived fats and protein, along with refined sugars.
You don’t need to be a nutrition expert to figure out how much healthier these statistics would look if the infographic was only focused on the average American VEGAN!
https://www.onegreenplanet.org/news/american-food-consumption-statistics-infographic/
Yes sugar have played a huge part in this as well but let's focus on meat for now since that is the topic. If we compare the population that is focused primarily on meat like the Eskimo's then they have a shorter lifespan compared to the longest living known population which is the people of Okinawan in the 1930's who primarily ate starches with fruits & vegetables before they adopted the western style of diet. The Eskimo's have also suffered from Cardio Vascular Disease(CVD) for centuries.
Ok so now we can come with the claim that we know somebody that smoked cigarettes and drank alcohol and lived to be a 100 just like with meat but that does not make cigarettes, alcohol or meat healthy. To determine what makes you live long time you need to do take a broader population into the study just like the study of the people of Okinawa.
"The Okinawa Diet: Living to 100"
The plant-based nature of the diet may trump the caloric restriction, though, since the one population that lives even longer than the Okinawa Japanese don’t just eat a 98% meat-free diet, they eat 100% meat-free. The Adventist vegetarians in California, with perhaps the highest life expectancy of any formally described population.
Adventist vegetarian men and women live to be about 83 and 86, comparable to Okinawan women, but better than Okinawan men. The best of the best were Adventist vegetarians who had healthy lifestyles too, like being exercising nonsmokers, 87 and nearly 90, on average. That’s like 10 to 14 years longer than the general population. Ten to 14 extra years on this Earth from simple lifestyle choices. And, this is happening now, in modern times, whereas Okinawan longevity is now a thing of the past. Okinawa now hosts more than a dozen KFCs.
https://nutritionfacts.org/video/the-okinawa-diet-living-to-100/
"Omega-3s & the Eskimo Fish Tale"
The fact is they never examined the cardiovascular status of the Eskimos; they just accepted at face value this notion that coronary atherosclerosis is almost unknown among the Eskimo, a concept that has been disproven over and over starting in the 30s. In fact, going back over a thousand years, we have frozen Eskimo mummies with atherosclerosis. Another from 500 years ago, a woman in her early 40s – atherosclerosis in her aorta and coronary arteries. And these aren’t just isolated cases. The totality of evidence from actual clinical investigations, autopsies, and imaging techniques is that they have the same plague of coronary artery disease that non Eskimo populations have, and actually have twice the fatal stroke rate and don’t live particularly long.
https://nutritionfacts.org/video/omega-3s-and-the-eskimo-fish-tale/
When it comes to the need of cholesterol then our bodies produce naturally 75-80% of the cholesterol that we need and the rest can be either consumed or created out of carbs, fats and proteins that all break down eventually and release carbon, which your liver turns into cholesterol.
"How it’s made: Cholesterol production in your body "
But to fully explain cholesterol, you need to realize that it's also vital to your health and well-being. Although we measure cholesterol production in the blood, it's found in every cell in the body. The Harvard Special Health Report Managing Your Cholesterol explains cholesterol as a waxy, whitish-yellow fat and a crucial building block in cell membranes. It's also used to make vitamin D, hormones (including testosterone and estrogen), and fat-dissolving bile acids. In fact, cholesterol production is so important that your liver and intestines make about 80% of the cholesterol you need to stay healthy. Only about 20% comes from the foods you eat.
https://www.health.harvard.edu/heart-health/how-its-made-cholesterol-production-in-your-body
"What's the difference between LDL and HDL cholesterol?"
Your body, mainly your liver, produces 75 percent of your cholesterol; your small intestine also aids in both the creation and absorption of cholesterol [source: AHA]. The average diet adds another 300 to 500 mg of cholesterol. This external cholesterol comes from animal and dairy products. But even if you eat foods without cholesterol, the carbs, fats and proteins all break down eventually and release carbon, which your liver turns into cholesterol.
Another thing that is relevant when it comes to cholesterol is of course carnitine and choline and the production of TMAO(trimethylamine-n-oxide) because of a certain gut bacteria which increases the risk for cholesterol buildup in our arteries and also prostate cancer in men. The very fact that vegans have less to no risk compared to omnivores of producing TMAO makes it a very strong indicator of why we are not designed for meat since TMAO is linked to heart attack, stroke, cancer and death.
"Carnitine, Choline, Cancer, & Cholesterol: The TMAO Connection"
What’s so bad about this TMAO stuff? Well, it may increase the risk of buildup of cholesterol in the inflammatory cells in the atherosclerotic plaques in our arteries, increasing our risk of heart attack, stroke, death—and, if that isn’t enough, cardiac surgery, as well.
So, how do you stay away from carnitine? Well, there’s zero dietary requirement; our body normally makes all that we need. The problem is that the bodies of other animals also makes all that they need, so when we eat them, their carnitine can end up in our gut for those bacteria to feast upon—resulting in TMAO. Some animals make more than others; carnitine is concentrated in red meat. So, then, why is there also clip art of white meat, dairy, and eggs?
That is what most media reports missed—even though it’s the very first sentence of the paper. How do you think the researchers even thought to look into carnitine? Because gut bacteria can turn choline into TMAO, too! Given the similarity in structure between carnitine and choline, they figured that the same kind of transformation would occur into TMAO. And, that’s exactly what they found.
“Eggs, milk, liver, red meat, poultry, shell fish, and fish,…[all] believed to be major dietary sources of choline, and, hence TMAO production.” So it’s not just red meat. The good news is that this may mean a new approach “to prevent or treat heart disease,” the most obvious of which would be “to limit dietary choline intake.” But, if that means decreasing egg, meat, and dairy consumption, then the new approach sounds an awful lot like the old approach.
Unlike carnitine, we do need to take in some choline, so should vegans be worried about the choline they’re getting from beans, veggies, grains, and fruit? And, same question with carnitine. There’s a small amount of carnitine found in fruits, veggies, and grains, as well. Of course, it’s not the carnitine itself we’re worried about, but the toxic TMAO, and you can feed a vegan a steak—literally, an eight-ounce sirloin (anything in the name of science). Same whopping carnitine load, but, essentially no TMAO was produced.
Apparently, the vegans don’t develop those TMAO-producing bacteria in their gut. And, why should they? It’s like the whole prebiotic story. You eat a lot of fiber, and you select for fiber-consuming bacteria. And, some of the compounds they make with fiber are beneficial, like the propionate I’ve talked about, that appears to have an anti-obesity effect.
https://nutritionfacts.org/video/carnitine-choline-cancer-and-cholesterol-the-tmao-connection/
Now the last item here that I will cover is brain development and in particular when it comes to the evolution to modern human. I think this response video to a TIME article really covered it well with cited sources. But suffice to say that anything that gave us enough energy(glucose) for the brain to develop further made us humans and what is the best and fastest source to create glucose if not complex carbs which cooked starches is very rich of.
"Sugar and the Brain"
Glucose, a form of sugar, is the primary source of energy for every cell in the body. Because the brain is so rich in nerve cells, or neurons, it is the most energy-demanding organ, using one-half of all the sugar energy in the body.
Brain functions such as thinking, memory, and learning are closely linked to glucose levels and how efficiently the brain uses this fuel source. If there isn’t enough glucose in the brain, for example, neurotransmitters, the brain’s chemical messengers, are not produced and communication between neurons breaks down. In addition, hypoglycemia, a common complication of diabetes caused by low glucose levels in the blood, can lead to loss of energy for brain function and is linked to poor attention and cognitive function.
"List of Foods That Are in the Starch Category"
Starchy foods, sometimes called complex carbohydrates, include grains, beans and legumes and starchy vegetables.
http://healthyeating.sfgate.com/list-foods-starch-category-10305.html
"TIME: Sorry Vegans, Meat Made Us Human Response"
For more info about a plant based eating go to http://truthseeker.se/questions-answers-veganism/ where I have a Q&A about veganism that touches upon some health related questions.