Reality Check: 5 Risks of a Raw Vegan Diet

Misconceptions of the philosophy of the raw vegan diet include the claim that raw foods are detoxifying and contain more "life energy"


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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.


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  1. 1. priddseren 04:14 PM 1/16/13

    In general most evidence for any of these diets are based on "clinical" studies and this makes all of them suspect. The bottom line is the human body is designed to digest meat and similar products and has a host of bacteria to digest plant products on behalf of the body. Considering evolution does not occur all that fast the best diet is likely to be a decent mix of everything in moderation with a slight bias to the diets of your ancestors. If you ancestors come from northern Europe where 6 months of the year only meat is available due to winter, then it is probably a bad idea to go on a diet similar to a place like India or even pre-columbian mexico because those places have plant products available year round.

    These extremes of veggies only or even meat only are likely to do nothing for you except cause problems.

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  2. 2. bbogart 12:39 PM 1/17/13

    "vital life energy" really? I never heard that argument from a raw vegan.

    1. Yes, "cooking" can increase the amount of some nutrients we can absorb. The question is what is meant by "cooking", 40C sounds a little too low to me. I think the maximum temperature on the earth (~55C) is a reasonable upper limit for raw food. Its quite possible that "raw" (warm room temperature) is the perfect balance between increasing some nutrients without destroying the others. Easy experiment to conduct... (if you have the equipment to measure the nutrients.)

    3. "detoxifying" is problematic in general.

    4. Similar issues with non-raw vegans and even vegetarians. Seems to me veggies are high in these minerals, nuts and seeds are raw and contain fatty acids. We (vegans) all know where B12 comes from: bacteria. "nuts" are high in fat? its all relative. What is the comparison between the fat content of beef and nuts for the same mass? I expect nuts are lower in fat. Still, we're not necessarily talking about a low-calorie vegan raw diet, and we do need some fat!

    5. What is "natural" is a key point of discussion and self-reflection for all vegans, in particular in the relation between wild, domesticated and "food" animals. *"impossible to survive on this diet without modern convenience"* This is a strong claim with no evidence.

    Regarding the the "big brain explosion" argument: Was not #4 referring to their being *too many* calories in nuts?? What about coconuts and avocados?

    Survival used to be about maximizing calories with the least risk and expense. In that framework, meat and cooking are obviously highly desirable. The point is that we are no longer fighting for survival, actually this engrained need for calories is actually decreasing our survival (obesity is just a manifestation of it). The arguments that big brains require more calories than a raw diet could provide don't hold any water for me. If big brains need more calories than raw-plant diets, then raw vegans should be wasting away. I don't buy that brain evolution takes more calories than brain maintenence. Evolution so slow and incremental, giving more than enough time for other aspects to adapt/develop. For example the greater ability to efficiently gather foods, evolution of digestive systems to be more effective, etc. Still what worked for early humans and apes have little to do with what works for us now.

    The bottom line is that if you're a raw vegan, a vegan or a vegetarian you have to pay attention to the nutrients you are consuming. Same thing goes for *any* other diet.

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  3. 3. rugeirn 12:26 PM 1/23/13

    "impossible to survive on this diet without modern convenience"* This is a strong claim with no evidence.

    Excusde me, but the evidence is all around you. Right now, I'm sitting here in Ann Arbor, MI. It's January and it's well below freezing outside. No raw vegetation that I can eat has been growing anywhere within a hundred miles of me since sometime last fall. How am I supposed to obtain my raw-vegan food? It doesn't fall from the sky. It has to be transported here, and kept edible along the way, and kept edible in my home, under these conditions.

    Yes, it does require "modern conveniences." Roads, trucks, refrigerators, packaging - these are all modern conveniences, and are absolutely necessary to life on this diet.

    Native Americans lived on the land where my house stands. They lived here on their own diet, unsupported by anything that we would call a modern convenience. They lived on a well-mixed diet that they could obtain from this land, in this climate. They did just fine.

    Any more evidence you want? Just open your eyes.

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  4. 4. rugeirn in reply to bbogart 12:29 PM 1/23/13

    "Never heard it from a raw vegan?"

    "Steve Factor, the Pure Energy Chef, will help you restore the vital life energy you were born with. Gourmet raw vegan food helps release pure energy in your body, mind, and spirit. In this ABOUT section read Steve's bio, his story of self-discovery. Enjoy an album of Steve's photos, as well as some mouth watering recipes for Steve's famous King Kong salads...with more to come." (from http://www.pureenergyfactor.com/about.)

    There. Now you have. All I had to do was search "raw vegan vital life energy" and it came up first on the list.

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  5. 5. IndyCA35 12:50 PM 1/23/13

    Look in a mirror. Your eyes face the front, like lions, wolves, bears, or T-Rex, and unlike a deer or cow.

    You are a carnivore or at least an omnivore.

    Vegan diets are not natural, cooked or otherwise.

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  6. 6. iWind in reply to bbogart 02:12 PM 1/24/13

    ""nuts" are high in fat? its all relative. What is the comparison between the fat content of beef and nuts for the same mass? I expect nuts are lower in fat."

    Oh, this was cute! It's not (nut?) really hard to check, even if you didn't know, and there's nothing relative about it at all. Nuts are generally more than 50% fat by weight. Macadamia nuts are more fatty than traditional butter!

    "Regarding the the "big brain explosion" argument: Was not #4 referring to their being *too many* calories in nuts?? What about coconuts and avocados?"

    If you can find any extended region of the world where nuts have been growing naturally in sufficient quantities to sustain even a small population of humans, I'd like to know where. Our far ancestors developed big brains *before* they could reap the benefits of agriculture, plantations and industrial harvesting.

    Much the same with avocados and coconuts. Although there may have been small patches here and there, where a pre-tribal community could sustain themselves well on naturally occurring energy-rich vegetation, such patches are unlikely to have been big enough to support long-term evolution of big brains.

    Indeed, there would have been little pressure to develop (very costly) big brains, if they did not use their brains for something more complicated than picking fruits. Any monkey can eat a raw avocado, unless it has allergies - if nutritious raw vegan food was so plentiful, what would they need a larger brain for? Was there some big evolutionary advantage in pontificating over Hegelian philosophy or something? For whatever reason(s) it happened, I'm pretty sure big brains didn't develop because there was a surplus and nature could find nothing better to do with it than produce zombie food.

    It is true, just because our ancestors didn't eat like that, doesn't mean we shouldn't, but you just can't combine that argument with the frequent claims that these are natural diets.

    It's curious, I've seen exactly the same chain of reasoning in support of "paleo" diets:
    "We should eat like this, because that's how our far ancestors ate, and [some argument about how therefore that is best for us]!"
    "But our ancestors didn't eat like that!"
    "Well, just because our ancestors didn't eat like that, it doesn't mean we shouldn't eat like that!"

    (Incidentally, "paleo" proselytes will also use the "I never heard that argument from any of us" argument, no matter how easy it is to find in a search.)

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  7. 7. bbogart 03:47 PM 1/24/13

    1. Yes, a raw vegan diet in some locations certainly requires lots of technical intervention. That does not mean that those diets require technical intervention in *all cases*. Living the way we all do in these cold climates also requires technical intervention. Living in cold climates requires everyone to use more resources than living in warm climates.

    2. Yes, google will allow you to find someone who says just about anything. I don't see how that validates the "vital live energy" statement. The quote above does not even state that the food as vital energy, but that it "release pure energy in your body, mind, and spirit." As far as I am concerned that statement has no meaning nor validity.

    I'm not going to argue that anything is "natural" for a human, as that term is highly problematic in the case of us "artificial apes".

    3. Front-pointing eyes: this theory is in dispute. Animals have different degrees at which their eyes face mostly front, and have mixed diets including mostly vegetation, eg. Loris, megabat, Lemur. These are by no means carnivores.

    4. Brain explosion: Again, I'm not arguing about some mythical "natural" human state (I don't believe such a thing exists at all). Yes, for enough calories to be foraged only a small population could evolve large brains. Just because the population it supports is "naturally" small does not make invalid.

    Evolution is slow, and it is entirely possible that brains increased in size in parallel with increases of methods to gather more calories. This could include hunting, or it could also include better navigational ability, communication for social structure, etc.

    Presumably great apes are the apex of non-human primates, thus their brains had to evolve to their large size (compared to "lesser" primates) by consuming more calories, and yet they are still largely herbivores. Of course you could argue that there is some hard threshold at which vegetative calories are no longer sufficient to evolve brains bigger than great apes. Again, I'm not arguing for "vegan == natural".

    Why did large brains develop? I have no idea, but that is irrelevant regarding the validity of a modern human's choice to consume a raw vegan diet.

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  8. 8. LisaViger in reply to IndyCA35 08:30 PM 1/25/13

    "Omnivore" simply means that an animal (human or nonhuman) is able to digest both plant and animal foods. Horses are technically omnivores. So are bears. Nearly all animals are omnivore and not all that many actually require animal foods. Cats, for example, are obligate carnivores, which means that have to have animal foods ... unless given taurine supplements. Incidentally, taurine is also completely destroyed by heat, so any cooked cat food must have taurine added to it.

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  9. 9. h1dden_blade 07:02 PM 3/13/13

    I know some one that says being vegan is the best thing in the world. I will show her this.

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