Reality Check: 5 Risks of a Raw Vegan Diet
On the road to good health, there are many forks. Some paths, such as vegetarianism or the Mediterranean diet, have considerable science supporting them. Others, such as the vegan or plant-based diet, which shuns all animal products including eggs and dairy, are winning converts.
And then there's a new offshoot, the raw vegan diet, which deems cooking to be unnatural and unhealthy.
An increasing number of celebrities — most recently, tennis sensation Venus Williams — swear by this diet as the best way to prevent and reverse diseases and to stay young and vital. Testimonials from ordinary folks are endless, boasting advantages along the lines of having more energy, better skin, improved relationships with woodland creatures and so on.
But on your road to good health, the raw vegan diet would likely be a U-turn. If you are already vegan or vegetarian, you have nothing to gain and much to lose by going totally or even mostly raw. Even doctors who prescribe and live by a vegan diet caution their patients against attempting a raw diet.
The reason? You would greatly reduce the types of foods you can eat. And you would do so in vain, because most of the raw vegan principles are based on misconceptions about human nutrition, and work counter to good health. [7 Medical Myths Even Doctors Believe]
This article addresses five such principles that are either half true or completely false.
What is raw veganism?
First, a primer: Raw veganism is a plant-based diet that involves no cooking. No food is heated above 104 degrees Fahrenheit (40 degrees Celsius). Foods are eaten fresh, dehydrated with low heat or fermented.
A core tenet of the diet is that heating food above 104 degrees not only diminishes its nutrients, but also makes the food toxic and less digestible. In raw vegan parlance, cooking is killing. Many raw vegans speak of "live" foods versus "dead" foods, and they aren't talking about sushi, so fresh it still wiggles.
Live or uncooked foods are said to be filled with vital life energy. In this way, raw veganism is an extension of the vegan appreciation for animal welfare, with the added spirituality of a life force, called chi or prana. Dead or cooked foods are said to be depleted of their life energy, as well as most of their nutrients.
Juicing and blending "green smoothies" often are key elements of this diet.
Now for the misconceptions:
Misconception #1: Cooking destroys nutrients
Sure, raw foods can be nutritious. But cooking breaks apart fibers and cellular walls to release nutrients that otherwise would be unavailable from the same raw food. Cooking tomatoes, for example, increases by five-fold the bioavailability of the antioxidant lycopene. Similarly, cooking carrots makes the beta-carotene they contain more available for the body to absorb. Soups are full of nutrients that would not be available in a pot of raw carrots, onions, parsnips and potatoes. [Science You Can Eat: 10 Interesting Facts About Food]
Cooking can also reduce certain chemicals in a vegetable that inhibit the absorption of minerals, including important minerals like zinc, iron, calcium and magnesium. Cooking spinach makes more iron and calcium available from its leaves, for example.
Admittedly, some nutrients are lost in cooking, such as vitamin C and certain B vitamins. But "plants are so excess in nutrients that even this breakdown is insignificant in practical terms," said John McDougall, creator of the McDougall Program, a vegan-friendly, starch-based diet.
And by eating both raw and cooked foods, "you get the best of both worlds," said Jennifer Nelson, director of clinical dietetics at the Mayo Clinic and associate professor of nutrition at the Mayo Medical School in Rochester, Minn.
Overcooking and charring can be a problem. Boiling the life out of greens will indeed reduce the nutrient load. And charring meats and vegetables creates cancer-causing chemicals. The solution, however, is not to stop all cooking, but rather to steam, lightly sauté or stir-fry vegetables, and to make more soups.
Fermenting or juicing raw foods also can make some nutrients more available, but that shouldn't deter from the fact that cooking is an ancient craft that makes some foods more digestible and nutritious.
As for the concept of life energy in raw food, this is a spiritual belief beyond the realm of science, so debating its benefit, let alone existence, would be futile.
Misconception #2: Cooking destroys enzymes
This one is absolutely true, but it doesn't matter. Yes, heat destroys enzymes. But humans make their own digestive enzymes to break down large food molecules into smaller ones.
The raw-enzyme logic itself breaks down when you consider that most humans cook food and that most humans are digesting that food reasonably well.
Ironically for the raw vegan, most of the plant enzymes in raw food get destroyed anyway in the acid of the human gut. Only a few make it to the small intestine. Fermented foods such as sauerkraut can carry enzymes into the gut. Their contribution to digestion is not zero, but it does appear to be minimal. "I know of no importance of plant enzymes in human digestion," said McDougall.
The enzyme theory for raw foods dates back to Edward Howell, a physician who published a book on enzymes in the 1940s, primarily citing research from the 1920s and 30s. We now know, however, that almost all nutrients are absorbed in the small intestine and that digestion at that stage relies almost entirely on human-generated bile and pancreatic enzymes.
A corollary myth is that humans have a finite number of enzymes and that, once they are used up, these enzymes are gone. This idea, too, was hatched by Howell. But where would this packet of enzymes reside? Howell never said. But in reality, humans make new enzymes throughout their lifetimes.
Misconception #3: Raw foods are detoxifying
Dietary detoxification is an alternative medicine concept with little scientific credibility. Usually, two organs are cited as needing detoxification: the liver and the colon. In reality, toxins can accumulate anywhere in the body, particularly in fat and fatty tissue, but also in proteins and bone.
The colon is surprisingly low in toxins, however. As for the liver, the confusion is that this organ "filters" toxins and must therefore, the reasoning goes, be loaded with toxins. But the liver is more of a chemical-processing plant than a filter; it breaks down toxins as they pass through. That is, the liver doesn't have extra toxins by virtue of it being the body's natural toxin-neutralizer. [Wishful Thinking: 6 'Magic Bullet' Cures That Don't Exist]
Another argument is that burning fat — in this case, on a raw vegan diet — would release toxins from the body. But fat cells don't burn up, as if into ashes, liberating their contents. Fats cells merely get bigger or smaller, depending on the amount of fatwithin the cell that's used.
It is unclear how much of a toxin, if any, would be set free if the fat molecule it is attached to is burned. The toxin is now free to attach to other fat molecules. If it does mobilize with other recently liberated toxins, in the case of extreme starvation, then the toxin could become toxic and overwhelm the liver.
In short, there are no foods or herbs that can magically bind and pull toxins from your blood or organs. The same would be true for cows or for any "vegan" animals that accumulate toxins in their fat; they don't cleanse themselves with their raw, plant-based diet.
At best, detoxification schemes (juicing, fasting) can help by virtue of not placing more toxins in our body for a day or two. And a healthful, plant-rich diet with plenty of water can, in general, help your liver and kidneys process and remove toxins more effectively, McDougall said.
Misconception #4: Raw veganism is healthful
Healthfulness when eating a raw, vegan diet is a challenge; it's not inherent. Many on the diet do lose weight by consuming fewer calories. But weight loss should not be the ultimate goal.
The most apparent problems are nutritional deficiencies, particularly for vitamins B12 and D, selenium, zinc, iron and two omega-3 fatty acids, DHA and EPA. Without taking supplements in pill form, it would be very difficult (and, for B12, impossible) to obtain a sufficient amount of these nutrients from raw, plant-based foods. [5 Key Nutrients Women Need as They Age]
Also, without access to a variety of foods year-round that can be eaten raw, one tends to rely on single-food sources.
"The problem with the raw food diet is where do you get your energy food?" asked Caldwell Esselstyn of the Cleveland Clinic, the doctor who convinced Bill Clinton to adopt a plant-based diet. "You get it from pouring down nuts," he said, and these are high in fat and not healthful when eaten in excess.
If it's not nuts, then it's bananas, which are healthful perhaps at a level of one or two per day, but not when providing the majority of your calories. Some people on a raw food diet rely so much on fruit that their teeth begin to erode: from acids in the fruits that wear down the tooth enamel, from sugar promoting decay, from dried fruit (another raw vegan staple) sticking to the teeth and further promoting decay, and from a general mineral deficiency.
The raw diet could be more healthful than the so-called S.A.D. ("standard American diet") of processed foods. But there is no evidence that, even given the resources to prepare a variety of raw foods daily, the raw vegan diet would be more healthful than the plant-based diets promoted by McDougall or Esselstyn, or than the diets that allow modest amounts of animal products.
Vegans would have to ask themselves what the added benefit would be from going raw if the raw diet offers no additional moral satisfaction, other than a reduced use of cooking fuel.
Misconception #5: Raw-only foods are natural
"No other animal cooks food," many a raw vegan has stated. One can just as well say that no other animal combines their kale and clover with tropical bananas in a high-speed blender to make the foods more palatable and digestible. Or, that no other animal plays chess.
Judging what is natural is a slippery slope. Humans around the world live to relatively similar ages on a multitude of different diets. Most of the reasonable diets that consist of grains, vegetables and meats will get you to at least age 70 if an accident orinfectious disease doesn't kill you first. A traditional, animal-based diet eaten by natives of Siberia is just as natural as a traditional diet eaten by unnamed tribes in the Amazon.
That said, no known human culture has ever attempted to survive solely on raw plant foods. It is the raw-only diet that is unnatural, because it is impossible to survive on this diet without modern conveniences such as refrigerators, storage devices and easy access to packaged foods — such as the aforementioned shelled nuts.
In fact, a child raised on a raw, vegan diet without proper supplementation would likely develop severe neurological and growth problems due to a lack of vitamin B12 and other nutrients. Adults who have eaten animal products for more than 20 years, by contrast, have the benefit of relying on bodily stores of certain key nutrients.
In a natural setting, without electricity, anyone located outside of a narrow belt of land near the equators, which have year-round growth potential, would need to dedicate their entire day to growing, gathering, preserving and storing food. Even around the tropics, where vegetation is plentiful, humans have been cooking as long as humans have been human — at least 200,000 years and likely longer in our hominid form.
Most scientists are in agreement that a combination of, first, eating meat and then cooking food enabled the development of the human brain. Cooking in particular opened up a new world of calories and nutrients. The human brain, after all, requires a lot of energy. [Eating Meat Made Us Human, Study Suggests]
Our raw-vegan cousin, the gorilla, has three times the body size of humans, but one-third the brain cells; it grew muscular on plants, but not smarter. According to a study published in October 2012, the gorilla would have needed to eat raw plants for more than 12 hours a day to consume enough calories to evolve a humanlike brain.
This myth busting is not intended to belittle the much-maligned raw vegan, but rather to inform rawists of the realities of this challenging diet.
Christopher Wanjek is the author of a new novel, "Hey, Einstein!", a comical nature-versus-nurture tale about raising clones of Albert Einstein in less-than-ideal settings. His column, Bad Medicine, appears regularly on LiveScience.
Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
The 100 Healthiest Foods on the Planet
By Eat This, Not That! Editors of Eat This, Not That! | 
Buying healthy food doesn't just mean you'll be eating delicious dishes; when you eat healthy foods, you help to improve your overall health—whether that's building muscle, sharpening your mind, or strengthening your heart.
The next time you drop by the market or order up a food delivery, make sure your grocery list contains as many of these foods as possible. The editors of Eat This, Not That! have crunched the nutritional numbers on every single food known to man to find you these 100 healthiest foods on the planet; each nutrient-dense food possesses special health-promoting powers to lead to your healthiest and happiest life.
And to discover the world's easiest ways to slim down, don't miss these 200 Best Weight Loss Tips!
© Twenty20The Peril of Palatability
The End of Overeating: Taking Control of the Insatiable American Diet, by David A. Kessler, Emmaus, Pa.: Rodale Books, 320 pages, $25.95
According to The Washington Post, David Kessler's research for The End of Overeating included late-night forays into the trash bins behind Chili's restaurants across California. From the chain's garbage he retrieved ingredient boxes with nutritional labels that revealed the secret of dishes such as Southwestern Eggrolls and Boneless Shanghai Wings. It turned out they "were bathed in salt, fat and sugars."
Kessler could have saved considerable time and trouble by paying a Chili's employee to write down this information for him. Or by visiting the Chili's website, which provides numbers for the calories, fat, saturated fat, carbohydrates, protein, fiber, and sodium in the company's food. Or simply by assuming that food promoted as a mouth-watering yet affordable indulgence probably has a lot of fat, salt, and sugar in it. But as The End of Overeating more than amply demonstrates, Kessler is the sort of crusader who spares no effort to uncover the obvious.
Kessler, a professor at the University of California at San Francisco's medical school, grabbed headlines as head of the Food and Drug Administration under Bill Clinton by taking on Big Tobacco. In this book he mounts an assault on Big Food, but the results are even feebler than his unsuccessful effort to regulate cigarettes without statutory authority. He combines banal observations, dressed up as scientific insights and revelations of corporate misdeeds, with presumptuous advice that overgeneralizes from his own troubled relationship with food.
Kessler urges readers to eschew pasta, French fries, bacon cheeseburgers, candy, and other "hyperpalatable" foods that he and some people he interviewed for the book have trouble consuming in moderation. Kessler wants us to know he is powerless over chocolate-chip cookies and "those fried dumplings at the San Francisco airport." Using himself and several similarly voracious acquaintances as models, he argues that "conditioned hypereating" is largely responsible for the "obesity epidemic." He exhorts its victims to resist the machinations of the food industry, "the manipulator of the consumers' minds and desires" (in the words of a "high-level food industry executive").
Kessler fearlessly accuses major restaurant chains of a crime they brag about, relying on unnamed "insiders" to reveal that comestible pushers such as Cinnabon and The Cheesecake Factory deliberately make their food delicious—or, as he breathlessly puts it, "design food specifically to be highly hedonic." Kessler certainly has the goods on the corporate conspiracy to serve people food they like. "We come up with craveable flavors, and the consumers come back, even days later," a "research chef at Chili's" confesses to him. Kessler also reveals that Nabisco lures Oreo eaters through a dastardly combination of sweet white filling and crunchy, bittersweet chocolate wafers, achieving "what's called dynamic contrast." Or maybe it's "what the industry calls 'dynamic novelty,'?" as Kessler claims in another Oreo discussion elsewhere in the book. Either way, it's so good it must be bad.
Not only do these sneaky bastards create irresistible food; they then turn around and tell people about it. "With its ability to create superstimuli, coupled with its marketing prowess, the industry has cracked the code of conditioned hypereating and learned exactly how to manipulate our eating behavior," Kessler writes. "It has figured out the programming that gets us to pursue the food it wants to sell."
If Kessler hadn't been so distracted by that plateful of chocolate-chip cookies, perhaps he would have noticed the contradiction between his description of how the food industry goes to great lengths to give consumers exactly what they want and his claim that it arbitrarily decides what products it wants to sell, then uses marketing magic to create a demand for them. The only way to deal with such logic-defying nefariousness, he suggests, is to regulate advertising and require restaurants to nag their customers with conspicuous calorie counts. He also encourages readers to "feel angry at the marketing and advertising techniques designed to get you to eat more, at the huge portion sizes served at restaurants, and at the layered and loaded food you encounter everywhere." It's all about "reframing seemingly well-meaning acts as hostile ones." Thinking back on all those times my mother offered me a second helping, I now realize how much she hates me.
Kessler's discussion of the science behind his theory of conditioned hypereating is at least as enlightening as his economic analysis of the food industry. "Palatable foods arouse our appetite," one expert tells him. "They act as an incentive to eat." Once he's made sure we know what palatable means, Kessler tries to explain why some foods have this quality. It turns out that palatable foods affect neurotransmitter levels, stimulate "the pleasure center," and activate "the body's reward system." Since the same could be said of pretty much everything that people enjoy, this observation is not very illuminating. It falls into the same true-but-dull category as Kessler's discovery that "people get fat because they eat more than people who are lean."
Kessler's neurological reductionism gives him an excuse to talk about rat studies and MRI scans, but it does not have much explanatory power. "The food we ate for comfort has left its mark on the brain, creating a void that will need to be filled the next time we are cued," he writes. "The result is a spiral of wanting." Since all experiences leave a "mark on the brain," what does this really tell us about why some people eat a few potato chips and stop, while others finish the bag and look for more in the cupboard?
It's not clear what percentage of the population reacts to food the way Kessler and his hypereating friends do. The government says two-thirds of Americans are "overweight," but that does not mean they routinely engage in the out-of-control gorging that Kessler describes. Then again, Kessler says "overeating is not the sole province of the overweight," since thin people can scarf down big bowls of ice cream or M&Ms but compensate by exercising more. It does not make much sense to claim that people who burn all the calories they consume are overeating—unless, like Kessler, you're promoting a trademarked treatment for overeating called Food Rehab™.
According to The Washington Post, "Kessler estimates that about 15 percent of the population is not affected" by conditioned hypereating, meaning 85 percent is. That seems inconsistent not only with everyday experience but with Kessler's own analysis of questionnaire data from the Reno Diet Heart Study. He says "one-third of the study population scored high" on one or more of three factors—"loss of control over eating," "lack of feeling satisfied by food," and "preoccupation with food"—that characterize the syndrome he typifies.
Yet the section of the book where Kessler describes his Food Rehab™ method seems to be aimed at a general audience, which is like expecting all drinkers to follow the 12 Steps of Alcoholics Anonymous. "I don't offer a one-size-fits-all technique," Kessler claims, adding that "few foods will be totally out of bounds." Yet he lays down some pretty categorical-sounding imperatives. "Neither sugar nor refined carbohydrates that behave much like sugar in the body, such as white flours and pasta, belong in the diet in significant amounts," he writes, calling for "a diet based largely on lean protein and whole grains or legumes, supplemented with fruits and nonstarchy vegetables." For everyone? Just for hypereaters? Maybe both, because by this point Kessler seems to have convinced himself that his impulsive, gluttonous reaction to tasty food is a universal trait.
But what about those of us who reject Kessler's ethic of rigidly ordered abstemiousness, which replaces hypereating with hypervigilance? Consider celebrity chef and food writer Anthony Bourdain, who supplied a blurb for this book ("disturbing, thought-provoking, and important") that suggests he hasn't read it. As anyone who watches No Reservations, Bourdain's show on the Travel Channel, can attest, his attitude toward food is about as far from Kessler's as it's possible to get. While Kessler says we should be wary of delicious dishes, Bourdain conspicuously consumes all manner of fatty, salty, calorie-packed food in large quantities without apology (and nevertheless keeps a trim figure). Bourdain's fans see a man who relishes life and refuses to sacrifice pleasure on the altar of health. Kessler presumably would see a victim of conditioned hypereating who desperately needs a course of Food Rehab™.
Senior Editor Jacob Sullum (jsullum@reason.com) is a nationally syndicated columnist.
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