Jane Says: If You Believe in Science, Don’t Go Paleo

פורסם: 7 ביוני 2014, 11:29 על ידי: Sustainability Org   [ עודכן 7 ביוני 2014, 11:30 ]

The logical basis for the diet of the moment ignores both evolution and anthropology.

Hardcore practitioners go full-on caveman, only eating raw meat. (Photo: Emmanuel Dunand/Getty Images)

January 30, 2013 By

“I’ve always enjoyed grains, beans, and other foods that are healthful—or so I’ve thought. But some Paleo friends of mine say that the foods eaten by our hunter-gatherer ancestors are much better for our bodies. What are your thoughts?”

—Erin Seward                                           

What our hunter-gatherer forebears may have eaten in the Paleolithic era (a.k.a. the Stone Age) allowed them to survive and thrive for millennia. But things took an unfortunate turn about 10,000 years ago, with the advent of agriculture and domestication of animals. Our bodies haven’t evolved fast enough to properly handle “new foods” such as grains, legumes, and dairy—let alone the additive-packed processed foods that fill supermarket shelves—so the key to optimal health is to return to a diet that is closer to that of our distant ancestors.

In a nutshell, that is the underlying premise of the Paleo Diet, which had its beginnings in The Stone Age Diet, written by gastroenterologist Walter Voegtlin and published in 1975. Overshadowed by regimens such as Atkins, South Beach, and Meat Lover’s, it didn’t really take off until a few years ago, with the publication of the bestselling Paleo Diet books by Dr. Loren Cordain. Although his website asserts he is “the world’s foremost authority on the evolutionary basis of diet and disease,” Dr. Cordain’s doctoral degree was in exercise physiology—not in medicine, the study of the Paleolithic era, or evolutionary biology. Still, these days, unless you’re living in a cave (sorry), you’ll trip over various Paleo permutations and their advocates everywhere you turn.

Eating plenty of fresh produce and lean meats and eliminating processed foods from your diet makes perfect sense—no wonder Paleos lose unwanted pounds, rack up a new personal best with each 10K, and generally feel reborn. But cutting out entire food groups such as whole grains, legumes, and dairy because our bodies stopped adapting 10,000 years ago? Is that how evolution works?

I turned to Professor Marlene Zuk, an actual evolutionary biologist who teaches at the University of Minnesota and is the author of the forthcoming Paleofantasy: What Evolution Really Tells Us About Sex, Diet, and How We Live. Her answer was a resounding no. “My research has led me into exploring the rates of evolution,” Zuk said in a phone interview. “And although I applaud people who are trying to be more thoughtful about what they eat, I’m a scientist and have to look at the data. You cannot assume that it’s impossible for us to change. Sometimes evolution is slow, sometimes it’s fast, sometimes it’s in between.”

“The poster child for quick evolution in humans is dairy tolerance,” she added helpfully. What she had to say on that matter was absolutely fascinating. I’m going to save it for another column, so stay tuned.

Now, where were we? We can’t assume that the Paleolithic era was a time of perfect dietary adaptation, either, Zuk noted. For starters, how much meat early humans ate and the ratio of meat to wild plants varied widely, depending on when those small, migratory bands occupied a 55,000-year-long timeline and where they roamed. Those in Ice Age Europe would have had different choices than their counterparts in a neotropical forest or on the African savanna. What’s for dinner tonight, hon—woolly mammoth, tapir, or gazelle? Oh. Termites, again? (Insects are a well-documented Paleolithic source of food that modern-day Paleos conveniently ignore.)

The diverse array of seasonal foods familiar to early humans would have included fibrous fruits, roots, bulbs, and tubers—one example being the cattail, a multi-use plant that Backwoods Home Magazine recognizes as the “super Wal-Mart of the swamp.”

As far as I’m concerned, the idea that there is essentially one Paleo Diet is up there with the equally ill-founded notion that there is one cuisine that defines India, say, or China. Proponents may put forth clear and logical—thus easy to understand—arguments, but that doesn’t necessarily make them correct.

Recently I spoke with Daphne Derven, an archaeologist and educator who enriches the food world on many different levels. “Among the Paleos, there seems to be a lack of appreciation of how intelligent and knowledgeable early humans were,” she said. “They were omnivores, which allowed them to adapt and thrive in ever-changing environments. They were bad-ass, taking down huge creatures. But they also knew that the seeds from a plant turned into the plant. They knew that tubers are more nutrient-dense than the plant itself. Other hominids [primates in the family Hominidae, which includes humans and their fossil ancestors] that had more specific niches in the ecology had less flexibility. They didn’t make it. The omnivores did. We are the ‘ready-for-anything’ species.”

Derven stressed that there is not a whole lot of evidence from the Paleolithic era, in large part because hunter-gatherers move around so much. But the archaeological record that exists has been studied very, very closely and with increasingly sophisticated methods. “Now we can look at teeth, bones, even seeds in the same context as tools,” she explained. “For instance, it turns out that the East African hominid species nicknamed ‘Nutcracker Man’ developed a powerful jaw and enormous molars not for cracking nuts, as was previously thought, but for chewing grasses, like a grazing animal. That was the main part of his diet.” Maybe the gazelle was just for special occasions.

One last thing: Let’s not forget to look at the big picture. If you view the Paleo Diet in a certain light, it can be construed as uncomfortably elitist. All that expensive meat—especially if you hew to the “only certified-organic and grass-fed” caveat—means that all of God’s children can’t come to the table. And, obviously, there are serious environmental consequences; in a recent Carnegie Mellon study, researchers found the start-to-finish process of raising and distributing red meat causes more greenhouse gas emission than any other food group. Termites, on the other hand...

סטייק = 4,000 ליטר מים
מחקר: צריכה של בשר מעובד מעלה את הסיכון למחלת לב
מחקר: קשר בין אכילת בשר אדום לתמותה מוקדמת
מחקר: צריכה של בשר מעובד מעלה את הסיכון למחלת לב
מציאות קשה לעיכול: כל הסיבות להוציא את הבשר מהצלחת
ארדן לשטייניץ: אל תפחית את המכס על מוצרי בשר
מהפכה מקדונלד'ס? אין באמת הבדל בין עוף לבקר
המבורגרים הם כמו "האמר" של ענף המזון
האם התיאבון שלנו לבשר הורס את כדור הארץ?
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