I believe you're correct that quality and quantity are part of the problem, but not the only problem.  It can be argued from an evolutionary biology point of view that we're very, very, very poorly suited to eating meat.  Our biology couldn't have known that we were going to invent knives, or discover/control fire.  Without tools and fire we'd be trying to kill animals with our bare hands, and then eat large chunks of meat raw.  If we could actually catch and kill the animal without weapons, and if we could actually chew the meat without utensils to a small enough chunk that we could eat it without choking, and if we didn't die from all the risks humans have from eating raw meat, then you'd have an argument.  Our intestines have approximately a 10:1 ratio with our "trunk" length (the distance from shoulders to hips), which is typical of an herbivore.  That means we absorb too much of the fats and cholesterol from meat, and we get disease from it.  Omnivores are far, far more likely to have heart disease and diabetes than vegetarians, and whole food vegans are essentially immune to both.  We are capable of practicing an omnivorous diet, but so is a cow.  But like a cow, we don't thrive on an omnivorous diet to the degree we do a whole food, plant-based diet.  The oldest living populations on the planet are the most plant-based populations.  Look at the Okinawans in Japan, they ate mostly plants and were the longest-living people in Japan.  The U.S. set up a bunch of military bases there, the available foods in grocery stores and local restaurants shifted heavily towards the western diet, many people in Okinawa shifted towards a western diet, and now they're some of the least healthy and shortest-living people in Japan.

You state that as if it's universally true, and it's not.  I love myself much more now that my diet and my ethics are in stronger alignment with each other.  And my iron, and my calcium, are stronger than ever before thanks to simply eating the plants that animals get their iron and their calcium from.

Where to begin...  vitamins come from plants and/or bacteria, not animals. Animals get their nutrients from eating plants (or eating animals that eat plants).  Going vegetarian will reduce your heart disease risk a little, and going vegan will reduce it a lot, as just one of many examples of how it is healthier.  (Like with any diet you have to do it right, there are unhealthy vegans, just as there are unhealthy omnivores, but a vegan diet done right is healthier than an omnivorous diet done right given the large number of diseases that are associated with eating animal products).

It's quite possible to lose weight on almost any diet.  That said, population studies show vegans having the greatest degree of success with weight management, and omnivores the least success.  So you can lose/manage weight as an omnivore, but most people on the Western diet nonetheless fail to do so.

EDIT TO ADD:  You're seriously complaining about the time it takes to cook a vegetarian/vegan?  Pulled pork wants to say hi.  Hell, there is a device popular in omnivorous diets called a slow cooker!  :)  I'd add, raw vegans in particular obviously don't waste much of people's time in cooking and preparation of food.

I knew it! Vegans are monster!!!

http://www.sciencealert.com/plants-really-do-respond-to-the-way-we-touch-them-scientists-reveal

Plants have feelings. How can you rip them apart.

Scrapking, i kinda agree with you, but on one point, with all pesticide & ogm, i am not sure they more safe than meat actually.

A Study in my country show 40% of the populate have pesticide permantly in blood atm...

Anyway i eat meat 1x per week and its enough ^^

What you describe is anecdotal.  There's a TV show called "Alone" where people are dumped in the wilderness alone and use cameras to document their struggles to survive, and multiple vegetarians have participated in the show and not ended up in a hospital for a week.  Your friend's experience could as easily have been because there was something wrong with the meat he ate.  There are countless examples of people who are vegetarian and/or vegan for years, and then switch back to an omnivorous diet without gastrointestinal distress.

Besides, it's far more likely that you'll die of heart disease, diabetes, or suffer poor quality of life due to a neurological disease that's highly correlated to eating animal products (Parkinson's, Alzheimers, Multiple Sclerosis, etc.) than you will find yourself in an unexpected survival scenario.  Heart disease is the #1 killer of omnivores, not unexpected survival scenarios.

Unless you know what you're doing, being an omnivore is very unhealthy.  Most supplements are taken by omnivores, do you think the gigantic piles of supplements Wal-Mart sells are going to vegans?  Omnivores are statistically the most nutrient deficient people.  Even the vaunted B12, as a greater proportion of omnivores are now B12 deficient than vegans.  None of the statistics I've read back up your argument.  And it makes sense, as plants contain a wider spectrum of nutrients than animal products do, so a diet that's higher in plants will be more nutritious.  You also absorb nutrients from plants than you do from animal products.  Yes, any diet can be bad, but the highest rates of food-related disease are in omnivorous populations.

The research doesn't back you up.  Even if there weren't proven health benefits to a whole food plant-based diet, there are health detriments that are all but solely associated with omnivorous diets.  It's possible to get all the nutrients you need on either a vegan diet, or an omnivorous diet, but cholesterol is only found in animal products, and plaque has been demonstrated to build up in the brain from the consumption of animal products and is being correlated to a raft of neurological disorders.

There's growing evidence that while MS may be caused by genetics, the rate at which symptoms progress (or not) is affected by diet for many people.  People diagnosed with the early stages of multiple sclerosis have symptoms stay the same or lesson in 95% of cases if they switch to a whole food plant-based diet, whereas MS patients who stay on an omnivorous diet see symptoms continue to worsen in almost 100% of cases.  That's stronger correlative evidence than we have for smoking causing cancer (as we have yet to "prove" that cigarettes cause cancer, as that would involve clinical trials where people were given cancer, so we've accepted the correlative evidence is strong enough and stopped there).  I don't want to be "that guy" who suggests a miracle cure to someone with a condition, yet the scientific evidence on this is strong and growing.

Poorly suited for eating meat, your canines tell me the opposite... Our Biology isn't a sentient entity that gets offended if we do something that isn't natural, it simply adapts to it changing us: the massive consumption of milk causes height to increase and bones to be stronger. A well trained human, even without tools is fully capable of killing with his bare hands small and medium sized animals but instead they decided to use tools  because they are more suited from an evolutionary standpoint:

1-tools are more efficent than bare hands, making it possible to kill an animal quicker and reducing the time of pain of the animal which is better from a moral standpoint;

2-tools can be used by any human and decrease the ammount of calories needed to hunt down the same animal, ending up in a larger profit in the ammount of energies gained from the food compared to the ones used to kill the animal.

Saying that we'd eat raw meat is again explained by evolution: Humans evolved--->discovered that Cooked meat is better than raw meat, Lions didn't evolve---> they can't use fire---->they can't find out the benefits of cooked meat.

I'd need some sources for the second half of your comment to give you a full response for example what species have that 10:1 ratio and if it even matters (but I have to say that humans are exceptions in many things, we are mammals but we don't go in lethargy, our Cubs don't start moving on their own right after birth etc. etc.) or the proves against eating meat because your comment is clearly full of Utopistic talk, and again, I like to make the example of Sardinia since I know it more it beeing part of my country to argue your Okinawa example: Sardinians are among some of the longest living human beeings in the world, their diet is full of meat and cheese (to be specific Pork, Sheeps and Salame are the most consumed foods by them) and one of their specialities is Casu Frazigu, a really fat cheese containing living worms...

I have a friend who is an omnivore and mostly eats refined carbohydrates and meats high in saturated fats.  He eats almost no fruits or vegetables whatsoever, and he looks like hell most of the time.  Does he somehow not need as careful attention to his nutrition and his growing "beer belly" (made entirely without eating beer) than a vegan?  Nope.  A vegan diet has *every* nutrient available to it.  Omnivorous diets are not magically more varied than vegan diets.  As I learned more about health and nutrition I went vegan, as I realized that there are no diseases associated with it, and yet there are many diseases associated with eating animal products.  My diet is both more restricted than it's ever been, but also more varied than it's ever been.

New evidence is suggesting that your statement about vegetarians/vegans needing to pay special attention to their protein intake is incorrect.  Proteins aren't one thing, they're combinations of amino acids.  The old thinking was that you had to make sure all amino acids were present in every meal, and that vegetarians/vegans had to do food combining (such as beans and rice, which together have a complete protein profile).  However, the new evidence is that the body is able to hang on to amino acids for a long time, probably for days at a time.  There's also new evidence that eating a complete protein at every meal is actually detrimental to the body, that eating some meals that are heavy in a small number of amino acids can actually have a cleansing effect on the body.

It's terribly difficult to do successful weight management with exercise, as the more you exercise the hungrier you get.  It can be done but requires tremendous discipline.  And there's a lot more to weight management than calorie intake.  When in the day you eat your calories is as important as what you eat, you can eat the right thing at the wrong time of day, as just one of many examples of what I mean.

There's growing evidence that meat makes most people sick.  It doesn't do it quickly, so the cause and effect is muddied for most people.  But there is a lot of disease that's caused by, or strongly correlated with, eating animal products.  Not the least of which is heart disease, but also diabetes and several neurological disorders.  It's normal for people in the West to eat a lot of animal products, but it's also normal for people to be sick later in life.  We associate this with old age, but other cultures don't traditionally have such a strong association with it.  That's because in cultures where people ate less meat, people were typically more vibrant in their old age.  In fact, the oldest living populations on the planet eat the least meat.

When we were hunter-gatherers, our diets were almost entirely plant-based in most parts of the planet.  The Inuit are an obvious exception, and examination of Inuit mummies show high amounts of diseases commonly associated with eating animal products.  Before we developed agriculture we didn't subsist primarily on vegetables, but we also didn't subsist primarily on animal products.  When we were hunter gatherers we subsisted (in most parts of the world) on nuts, and berries, and bark, and seeds, and that sort of thing.  This stuff was incredibly nutritious.  There is evidence that cultures that went from being primarily gatherers, to being agrarian, lost several inches of height in the following generations since the things that can be easily farmed (wheat, corn, animals, etc.) are drastically less nutritious than the diets we had as gatherers.  We've adapted somewhat to subsisting on less nutrition, but it's taken us thousands of generations to do so. 

I agree that there is evidence that microwave ovens may be a no-no.  More research needs to be done, but your claim may ultimate prove to be correct.  I also agree that drinking large amounts of water can be very good for health.  I agree that a raw diet can be exceptionally good.  I strongly agree that refined sugars are a blight on our health.  I disagree with the rest.

Eating washed vegetables denies you lots of micronutrients.  One example is vitamin B12 which is synthesized in your body from bacteria in the ground.  If you're eating local, organic produce,  you probably just need to brush it off to leave trace amounts of bacteria and micronutrients, rather than wash it.

There's not a lot of evidence yet, IMO, that everyone benefits from gluten being removed from their diets.  There are suggestions that some people do, however.  Just not everyone.

Studies suggest that there is no diet as effective at warding off disease as a whole food, plant-based diet.  So suggesting that there's no benefit to that is incorrect, based on the science.

There's no need for meat in one's diet.  There's no nutrient that's exclusive to meat.  There's no health benefit exclusive to meat.  There's strong and growing evidence that we're descended from herbivores, not the least of which is our intestines are too long to safely consume meat.  They've attempted to give dogs coronary heart disease from eating nothing but large quantities of fatty meats in controlled conditions, and they've failed because (like other ominvores) dogs have short intestines.  Humans, like other biological herbivores, have long intestines that mean we get too much of the fat and cholesterol when we eat meat.  In one study, hundreds of participants were put on a whole food plant-based diet, and those that dropped out of the study went on to have high instances of heart attack and stroke.  Of those who remained in the study, only 0.06% of them had a cardiac event.

Humans don't have canines by any reasonable definition.  They're called that by the dental community, but that's meaningless from the perspective of evolutionary biology.  In dogs, the canine teeth are 2-3 times longer and drastically sharper.  Human "canines" are not substantially longer than the rest of our teeth, nor are they sharp enough to tear and rend meat well.  And the gorilla, which is broadly accepted as an herbivore, has "canines" that are much longer and much sharper.  Basically, some human teeth are nicknamed "canines", but that's not at all relevant to our evolutionary biology.

Omnivores and carnivores can taste protein, humans can't.  We don't have protein receptors on our tongue, so when we eat meat what we're tasting are the fats and salts.  Meat is sufficiently poorly tasting to us that we choose to "season" it, which in most cases means adding plants to it to make it taste better!  :)

Length of intestines matters a great deal.  Our intestines are the smoking gun: they're not designed to process meat safely.  They're too long, they absorb too much of the cholesterol and other negatives of meat.  Controlled experiments have failed to give coronary heart disease to dogs (which are an omnivore) (Citation:  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603726/), yet it's become the number one killer of people in the western world.  I'd say that that "matters".

It's not in question that we ate more meat starting from when we were able to kill it with weapons, cut it, and cook it.  The real question is whether we ate much meat at all prior to that, and the evidence predominantly suggests we didn't.  And that's part of why we're poorly suited to eating it to this day, as that was a blink of an eye ago from an evolutionary point of view.

Here are some sources.

As the Okinawans ate more meat, their health declined rapidly:  http://www.ncbi.nlm.nih.gov/pubmed/19533867

The longest-living population on record ate the most plants/least animal products:  http://archinte.jamanetwork.com/article.aspx?articleid=648593

It's possible to have exceptions without disproving the rule.  I haven't researched the Sardinian diet, but the "blue zones" are heavily skewed towards populations that eat very little in the way of animal products:  https://www.bluezones.com/2009/04/cnn-secrets-to-a-long-life-plant-based-diet/

One study showed vegans had 26% less heart disease and 68% less diabetes:  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4073139/

Here is a comparison of human traits relative to herbivores, omnivores, and carnivores: http://www.ecologos.org/anatomy.htm

In summation, the preponderence of evidence supports the idea that an omnivorous diet is less healthful than a whole food, plant-based diet.

If that's true (that most overweight people are not vegan) it has nothing to do with the diet and more to do with the fact that vegans represent a very small amount of the population. They're also much more inclined, by nature of their living choice, to focus ON their diets.

If you look at the worlds greatest athletes, almost all of them are eating lean meat. These are people with 2% body fat and abs so ripped, you could shred cheese on them. Body builders, olympians... almost every one of them are eating lean meats. 

If a person wants to lose weight, eating 1,000 calories a day will do it. You could eat oeros, milk shakes, cheese burgers, drink Coke or Pepsi... but if you stay at 1,000 calories, you'll lose weight. Now, will you be healthy? No, not at all. But that's a different topic. I understand and know not all calories are the same but I wasn't talking about health. I was simply talking about losing weight and being trim. 

Some vegans walk around, shouting on the roof tops and street corners about how they're trim solely because they don't eat meat which is an absolute and utter LIE. It's not about meat or no meat. It's about hard work and proper diet. That's all I'm saying.

Pesticides accumulate up the food chain, so when you eat an animal you're getting pesticides and herbicides it was directly exposed to, plus what it retained from the grain and other food it ate.  So there's no way that meat is safer on that point.  And of course, there are pesticide and GMO-free plant-based foods (so-called "organic" produce).

Since animals eat vast quantities of plant-based foods in creating animal agriculture products, to the degree that someone is concerned about it they should go vegan.  One third of the world's grain goes to livestock.  A cow will eat as much as 500 times as much food energy as we get out of eating the cow.  So if you believe plants have feelings, that's a strong argument to go vegan.  I suspect you weren't being serious, however, despite your argument working against itself.