Dr. McDougall: Meat in the Human Diet
Some excerpts:
Quote:
Many scientists use the diet of our ancestors as the justification for what we should eat today. That may be a useful approach, but which ancestors are we to follow? Differences of opinion arise because throughout human history people have consumed a wide variety of foods. The early ancestors of modern humans, from at least 4 million years ago, followed diets almost exclusively of plant-foods. Beginning at least 250,000 years ago, many of the hunter-gatherer societies consumed meat as a large part of their diet.1 However, more recently, over the past 12,000 years of agricultural development, people’s diets have been mostly based upon starches, like rice in Asia, corn in North America, potatoes in western parts of South America, wheat in Europe and Northern Africa. In terms of the time line of evolution, 12,000 years, and even 250,000 years, is only a brief moment.
Quote:
Because many hunter-gatherer societies obtained most of their calories from the fat of meat does not mean meat is the ideal diet for modern people. Almost every scientist readily admits that the composition of wild game available to our ancestors was far different from the grain-fed domesticated high-fat meat people eat these days. Furthermore, even if humans have been eating meat for centuries, it has not been with the ease that wealthy Westerners acquire it today. Without refrigeration and other means of preserving meat in a near fresh state, consumption was limited to within a few days of the kill – until the meat spoiled. (With the advent of fire people learned to preserve meat by smoking it.)
During difficult times meat provided more benefits than harms, but in a society where food is plentiful and life is physically easy, meat can become a serious health hazard. A traditional Arctic Eskimo, living in a subfreezing climate, could expend 6000 calories and more a day just to keep warm and hunt for food. The high-fat animal food sources – fish, walrus, whale, and seal – from his local environment were the most practical means of meeting the demands of those rigorous surroundings. Modern Eskimos living in heated houses and driving around in their climate-controlled SUVs, still consuming a high-meat diet, have become some of the fattest and sickest people on earth. Of course, they now use a “green lure” (a $10 bill) to catch their fish (sandwich).
Quote:
Our dentition evolved for processing starches, fruits, and vegetables, not tearing and masticating flesh. Our oft-cited "canine" teeth are not at all comparable to the sharp teeth of true carnivores. I lecture to over 10,000 dentists, dental hygienists, and oral specialists every year, and I always ask them to show me the “canine” teeth in a person’s mouth – those that resemble a cat’s or dog’s teeth – I am still waiting to be shown the first example of a sharply pointed canine tooth.
If you have any doubt of the truth of this observation then go look in the mirror right now – you may have learned to call your 4 corner front teeth, “canine teeth” – but in no way do they resemble the sharp, jagged, blades of a true carnivore – your corner teeth are short, blunted, and flat on top (or slightly rounded at most). Nor do they ever function in the manner of true canine teeth. Have you ever observed someone purposely favoring these teeth while tearing off a piece of steak or chewing it? Nor have I. The lower jaw of a meat-eating animal has very little side-to-side motion – it is fixed to open and close, which adds strength and stability to its powerful bite. Like other plant-eating animals our jaw can move forwards and backwards, and side-to-side, as well as open and close, for biting off pieces of plant matter, and then grinding them into smaller pieces with our flat molars.
In a failed attempt to chew and swallow pieces of food, usually meat, approximately 4,000 people die each year in the U.S.14 They choke on inadequately masticated chunks that become stuck in their throats. The Heimlich maneuver was specifically designed to save the lives of people dying from these “café coronaries.”14.
Quote:
Cholesterol is only found in animal foods – no plant contains cholesterol. The liver and biliary system of a meat-eating animal has an unlimited capacity to process and excrete cholesterol from its body – it goes out, in the bile, passing through the bile ducts and gallbladder, into the intestine, and finally, out with the stool. For example, you can feed a dog or cat pure egg yolks all day long and they will easily get rid of all of it and never suffer from a backup of cholesterol. Humans, like other plant-eating animals, have livers with very limited capacities for cholesterol removal – they can remove only a little more than they make for themselves for their own bodies – and as a result, most people have great difficulty eliminating the extra cholesterol they take in from eating animal products. This apparent “inefficiency” is because humans have evolved on a diet of mostly plant foods (containing no cholesterol), and therefore, they never required a highly efficient cholesterol-eliminating biliary system. The resulting cholesterol buildup, when people eat meat, causes deposits in the arteries (atherosclerosis), in the skin under the eyes (xanthelasma), and in the tendons. Bile supersaturated with cholesterol forms gallstones (over 90% of gallstones are made of cholesterol). About half of all middle-aged women who live on the Western diet have cholesterol gallstones. (See my April and May 2002 Newsletters.)
Quote:
When plants have been for eons a plentiful and reliable part of the diet, an animal can become dependent upon specific nutrients found in these foods. For example, ascorbic acid – found preformed and ready to use in plant foods – is called vitamin C in the diet of people. Insufficient amounts of this vitamin cause scurvy. Vitamins are essential micronutrients that cannot be synthesized by the body; and therefore, must be in the food. Because ascorbic acid has not been reliably available to them, meat-eating animals have retained the ability to synthesize ascorbic acid from basic raw materials found in their meat diet – therefore, it is not a vitamin for them. (In other words it is not “vital” or essential to be preformed in their food supply.)
Because humans have lived throughout most of their evolution on diets with very little animal matter, they have had to develop or retain the ability to synthesize some substances they need that are abundantly found in meat. For example, humans, and other plant-eating animals, have the ability to make vitamin A from a precursor found in large quantities in plants, called beta-carotene. Carnivores cannot utilize beta-carotene as a precursor of vitamin A. They have no need to; throughout their evolution they have always had a plentiful supply of preformed vitamin A (Retinol) found in the meat.
Quote:
Our Instincts Are for Plants
For most enlightened people in modern Western nations, the idea of chasing down and killing an animal is revolting; and the thought of consuming that freshly killed flesh is repulsive. (And to eat decaying flesh, as a vulture does, would be next to impossible.) Even when meat is cooked, most people are disgusted by the thought of eating a slice of horse, kangaroo, rat, or cat. Cows, chickens and pigs are acceptable to most Westerners only because we have eaten them all of our lives. Yet even then, to make meat palatable, its true nature must be covered up with a strong flavored sauce made with salt, sugar, and/or spices – like sweet and sour, marinara, barbecue, or steak sauce.
Quote:
People do not have a negative reaction to unfamiliar fruits and vegetables. Consider, I could ask you to try an unfamiliar “star fruit” from the tropics for the first time and you would eat and enjoy it without hesitation. Why? Because your natural instincts are to eat fruits and vegetables.
Quote:
Our hands are made for gathering plants, not ripping flesh. We cool ourselves by sweating, like most other plant-eating animals. Carnivores cool their bodies by panting. We drink our beverages by sipping, not lapping like a dog or cat. The exhaustive factual comparisons of our body traits with that of other animals prove we have evolved over eons in an environment of plant-based foods – the only real contradiction is our behavior.