NOTE: The original version of this book review was criticized for not making it clear when I was simply reporting the book’s content and when I was expressing support for one of its arguments. I have revised it to make it more clear. The additions are marked by brackets.
Vegetarians come in several flavors. Ovo-vegetarians eat eggs, lacto-vegetarians eat dairy products but not eggs, ovo-lacto-vegetarians eat both eggs and dairy products. Pescatarians eat fish but no other animals. Vegans eat nothing derived from animals. Vegans have claimed that a plants-only diet offers a multitude of health benefits, is better for the environment, and is the only ethical choice. While some of them respect the dietary choices of others, some of them proselytize with religious-like fervor and are working to get their diet adopted by all of humanity. In her new book, Vegan Betrayal: Love, Lies, And Hunger In A Plants-Only World, Mara Kahn questions those beliefs, pointing out that no human population has ever endured on a plants-only diet; that while some studies have shown short-term health benefits, long-term follow-up is missing; that long-term vegans frequently experience “failure to thrive,” go off their diet, and feel better when they return to eating meat; and that veganism might actually harm the environment and might not even save animal lives overall.
The book is really three books interleaved into one:
- The story of her own experiences as a vegan.
- An evidence-supported analysis of veganism and vegetarianism
- Some rather woo-woo ideas about finding a unique diet for each individual
I can highly recommend the first two, but I deplore the third.
Her personal story
At age 19, she went to Europe alone, backpacking, hitchhiking, and falling under the spell of a new acquaintance who persuaded her to become a vegan. She returned home and shocked her very conventional family by refusing to shave her hairy armpits, wear a bra, or eat any food derived from an animal. She is a great storyteller; her vivid recollections are described in colorful language and are often hilariously funny. I very much enjoyed the anecdotes of her life in various parts of the world first as a vegan, then as a vegetarian. Eventually she realized that her health was suffering and in slow steps she gradually incorporated more and more animal foods into her diet.
She says, “I never missed the taste of meat, not once. What I did miss was the after-meal sensation of being energized and well nourished.” She experienced “overwhelming protein/fat hunger,” and tried to satisfy it with yogurt and coffee.
Much of the [published nutritional] research is faulty[, according to Kahn]: in some studies, vegetarians are lumped with vegans and occasional meat-eaters. Not one respected study has ever shown a long-term vegan diet to be healthier than any other, and most research uncovers troubling deficiencies. They claim meat-free diets are healthier, but healthier than what? Than the typical unhealthy American diet [?]
Control for lifestyle habits, as every useful nutrition study must, and then compare a vegetarian or vegan diet to one of whole plants and judicious amounts of wild-caught fish or pastured meat—like the seafood-loving Mediterranean diet or the animal-adoring French diet—and the health advantages either disappear or are greatly surpassed.
[Kahn says] research has shown vegan deficits in many key nutrients including iodine, iron, zinc, taurine, vitamins A, D and B12, selenium, protein, calcium and omega-3 fatty acids. Yes, it is possible to get adequate nutrition from a vegan diet; but in practice, many vegans don’t. She observes vegans eating huge amounts of carbs and vegan junk foods and skimping on their protein and vitamin needs. This is particularly a concern for teenage girls who are still growing; teenage girls are a big part of the vegetarian demographic.
[She says] a famous Seventh-day Adventist study found that “vegetarians live longer than meat-eaters,” but fish eaters were lumped with vegetarians and they live even longer. And there are plenty of other groups that eat meat and live longer than Seventh-day Adventists, including Okinawans and Sardinians. No studies show that veganism is the healthiest of diets and some suggest that it is not.
[Kahn reports that] more and more disillusioned ex-vegans are offering testimonials like Angelina Jolie’s claim that an all-plants diet “nearly killed me.” [She hypothesizes that] vegans may feel better at first simply because they are eating fewer calories and have replaced processed and junk foods with healthier fruits, vegetables, and grains. But the feeling doesn’t last.
[She points out that] the standard nutritional recommendations to eat more veggies and fruits are about adding more plants to the diet, not about eating only plants.
Bottom line: Research shows that a mainly plant-based diet is healthy, but the findings can’t be used to justify a plants-only diet. [I agree with this conclusion.]
Vegans are often malnourished
[Kahn reports that] there is a high dropout rate. “Once you pull out all animal-sourced food, a whole lot of nutrients have suddenly gone missing or exist in deficient amounts.”
While it is possible to get adequate nutrition from plants alone, it requires a lot of knowledge and discipline, and in practice many vegetarians begin to suffer from insidious borderline malnutrition.
Kahn argues that dietary recommendations tend to underestimate the amount of protein needed for health. When vegans get hungry they tend to gorge on carbs when what they need is protein.
“Too-thin vegans are eating animal flesh after all: their own.” Protein starvation leads to self-cannibalization.
Vegans often rely on soy for protein, but soy can [sometimes] be harmful to health in various ways [although it does also have proven health benefits]. One of the prominent side effects of all-plant diets is flatulence, which can range from a mild inconvenience to a serious problem.
It may be possible for individuals with naturally lower protein needs who can tolerate large amounts of legumes, lead low-stress lives (a low-stress life, what’s that?) and keep a vigilant eye on daily quantity, quality, and amino acid completeness. Easy? No, it is not.
Arguments from evolution
[Kahn finds vegan arguments from evolution unconvincing. I agree. What follows reflects my own thoughts on the subject:] You may have heard vegans, fruitarians, or other food faddists claim that humans were not designed to eat meat. They cite our lack of fangs and claws for bringing down prey. Admittedly, humans are not carnivores, although they can thrive on a diet of raw meat alone. Humans aren’t herbivores either: they lack the rumens and multiple stomachs of animals like cows. Cows are equipped to eat a 100% plant-based diet; humans are not. Raw food faddists argue that humans didn’t evolve to eat cooked food, ignoring the fact that cooking makes some nutrients more available and food more digestible. Demonizers of wheat argue that our ancestors were hunters/gatherers, not farmers.
Some argue that we can’t digest meat; that’s simply not true. We can and do digest it. Plant protein is actually less digestible than meat protein.
Arguments from evolution tend to miss the point: humans are not carnivores or herbivores, but omnivores. Evolution equipped us to thrive on a wide variety of diets. Our ability to eat whatever foods were available allowed us to survive in very diverse environments.
History and purity
Kahn delves into the history of vegetarianism and veganism. Much of it is bound up with ideals of purity. Fasts and dietary prohibitions, food-related rituals, and purification rites have been prominent in most religions. Pythagoras’ followers could eat meat, but not bone marrow, because they believed it concealed messages from the gods. For them, it was beans that were absolutely prohibited. Go figure!
In some cultures, specific animals and foods were endowed with special meanings. Group cohesiveness was promoted when hunters distributed meat to others in their tribe. Shared meals have an important social function in today’s world, from family dinners to wedding celebrations and Thanksgiving feasts. Our dietary choices and customs are more emotion-driven than fact-driven.
As human history progressed, the circle of compassion enlarged to include animals. I think it’s fair to say that the majority of vegans and vegetarians chose their path mainly because they are repelled by the idea of killing animals. But [Kahn suggests that] perhaps they should examine their conscience more closely.
Don’t they realize they are eating animals in many plant foods? The FDA allows 60 insect fragments per 100 gram candy bar; 225 insect parts and 4.5 rodent hairs or excreta per 100 g pasta; 10 whole insects and 35 fly eggs per 8 ounces of raisins.
To be consistent maybe vegans should be more reluctant to kill plants. [As Kahn reports,] new research indicates that plants have a degree of awareness, change their behavior in response to environmental conditions, communicate with other plants by chemical signals, and [some researchers have even suggested they] may perceive pain. [These are intriguing findings, but I don’t see any reason to believe plants can suffer.]
Our food choices involve ethics, no doubt about that, but trying to impose a single moral code of eating on all people is profoundly unethical. In following a well-planned vegan diet, an unknown percentage of us will suffer, our health and quality of life. Surely the compassion that lies at the heart of ethical veganism extends to human animals.
It is generally accepted that plants-only diets are better for the environment. [Kahn suggests that] that may not be true.
Even if you repudiate the eating of animals, you are killing animals by proxy at every meal. Consider the field mice, pheasants, snakes and tender young rabbits—all of the innocent wild beings diced and sliced by the tiller that prepares the soil for your favorite grains.
If we gradually moved to the larger foraging mammals only, … and raised them on their natural diet of 100% grass using a no-till, pasture-forage model, this might mean fewer total animals killed (domestic and wild) than in the all-vegan model. Let’s give this intriguing idea a closer look.” [she goes on to present a plausible argument] [Note: I have not researched this and won’t venture a personal opinion.]
She argues for ethical hunters, sustainable agriculture, abolishing factory farms, and being kind to the animals we are going to eat.
On the subject of veganism, Kahn’s information is evidence-based and reliable and her reasoning plausible; but unfortunately when she turns to other subjects she goes off the rails. Her concerns about GMOs, glyphosate, sugar, fructose, wheat, “inflammatory” foods, and bottle-feeding are alarmist and not based on rigorous science. She quotes unreliable sources like an Ayurvedic doctor and Weston Price. She consults a TCM practitioner. Her criticism of statin drugs is misguided. She believes in superfoods and bioidentical hormones. She talks of adrenal exhaustion and yeast overgrowth.
She consults a naturopath for nutritional advice and is given homeopathic remedies. She thinks there are proven benefits of guided imagery; there aren’t. She cites a study where guided imagery and therapeutic touch (!) were used to treat PTSD in soldiers. She consults medical intuitives. They intuit that she should increase her intake of fat and protein, but she refuses to follow that advice until it is echoed by an MD she believes is knowledgeable about nutrition, Dr. Diane Schwarzbein. She believes acupuncture was effective in restoring her daughter’s absent menses. She believes in metabolic typing tests and diets based on metabolic type. She stresses bioindividuality (i.e., you are so unique that studies don’t apply to you). She thinks all the cells of the body are conscious, and you can rely on the wisdom of the body to tell you what foods your body uniquely requires.
The real problem
What I really could not bear at such a tender young age was the biological truth of our earthly existence. Every creature is food for others, including me, including you… the vegan argument is, in fact, is a profound denial of nature. We are animals. And our living and dying and nourishing are utterly entangled with other animals.
She now accepts her participation in this natural cycle with a conscious and reverent approach.
Ideology can be persuasive, but harsh reality often ruins an appealing idea. People can die from fanatical diet beliefs.
What did my own journey teach a comically naïve if earnest youth who thirsted for carnal knowledge and hungered to abolish all animal suffering? Its hard truth was this: the very real dangers of a rigid ideology, born of the mind and the emotions, which does not line up with the biological realities of the body. For as much as I longed to honor and respect my animal brethren by not eating them, the earthly reality is that I need to do exactly that.
I wish I could recommend this book for its funny, engaging human story and its trenchant analysis of plants-only diets, but the later chapters are contaminated with beliefs not based on scientific evidence. Too bad! [She is an excellent writer, and it might have been an excellent book if she had asked science-based reviewers to critique the more wooish subjects during the editing process.] I agree with the author that the evidence for health and environmental benefits and the ethical and evolutionary arguments are insufficient to justify a plants-only diet [for the whole population. Those who choose a plants-only diet for whatever reasons can thrive on it, but only if they are careful to ensure good nutrition.]
This article was originally published in the Science-Based Medicine Blog.