Thursday, September 11, 2014

Future of Food Series Part IV: The Evolution of Diet

by Sarah Janes Ugoretz

This week, we return to our exploration of National Geographic’s Future of Food series. In the latest featured article, “The Evolution of Diet,” Ann Gibbons—author of The First Human: The Race to Discover Our Earliest Ancestors—opens the discussion with a simple question: “Could eating like our ancestors make us healthier?” This is an incredibly timely conversation of a topic that has gained quite a bit of attention as of late. I’m referring of course to the Paleolithic Diet, better known by its abbreviated form—the Paleo Diet. Paleoanthropologist Peter Ungar of the University of Arkansas sheds some light on the craze surrounding this new Stone Age-inspired diet. One of the principle tenants underlying the Paleo Diet is the idea that we modern humans have not had sufficient time to evolve from hunter-gatherers to those who consume farmed foods. Supporters often ground this point in a discussion surrounding the general youthfulness of agriculture—it only came to the fore about 10,000 years ago. One of the Paleo Diet’s staunchest advocates, Loren Cordain, an evolutionary nutritionist at Colorado State University, draws from modern-day studies he has conducted on traditional hunter-gatherer societies. Having found that 73 percent of the societies he studied obtained at least 50 percent of their daily caloric intake from meat, Cordain thereby encourages his fellow humans to focus on eating lean meat and fish, while limiting intake of beans, cereal grains and dairy products. Doing so, he insists, will allow us to avoid the “diseases of civilization”—heart disease, high blood pressure, diabetes and cancer.

Numerous studies, including a few referenced in this piece by Gibbons, partly substantiate Cordain’s findings—that eating a diet of non-processed foods can help us avoid these so-called diseases of modern civilization. However, researchers are less quick to get behind Cordain’s and the Paleo Diet’s meat-centric ideology. Gibbons lays out one of the major unwavering concerns here, which I touched on back in July: with the global population expected to reach nine billion by 2050, we need to ask ourselves which diet is best. “Simply put, a diet that revolves around meat and dairy, a way of eating that’s on the rise throughout the developing world, will take a greater toll on the world’s resources than one that revolves around unrefined grains, nuts, fruits, and vegetables.”

Moreover, if you look deeper into what academic studies on both historic and modern hunter-gatherer societies have found, they echo what Gibbons has said: that “the real Paleolithic diet wasn’t all meat and marrow.” While it appears that hunter-gathers the world over crave meat more than any other food, the amount of meat they are actually able to secure and consume on a regular basis varies widely. Overall, researchers have estimated that meat provides around 30 percent of their annual caloric intake (with the notable exception of the Inuit and other groups residing in the Arctic, who typically obtain 99 percent of their calories from seals, narwhals and fish). Amanda Henry, a paleobiologist at the Max Planck Institute for Evolutionary Anthropology points out that: “There’s been a consistent story about hunting defining us and that meat made us human.” This picture, however, is incomplete. We are instead reminded that man the hunter is backed up by woman the gatherer, and that during lean times, what these societies really subsist on are plant foods.

Speaking directly to and perhaps contradicting one of the arguments that advocates of the Paleo Diet make—that humans are not evolved enough to eat grains and other farmed foods—Henry has identified the presence of starch granules on fossil teeth and on stone tools dating back 100,000 years. These findings suggest that humans may indeed have been consuming grains and other plant foods long enough to have evolved the ability to tolerate them. “What bothers a lot of paleoanthropologists is that we actually didn’t have just one caveman diet,” says Leslie Aiello, president of the Wenner-Gren Foundation for Anthropological Research. “The human diet goes back at least two million years. We had a lot of cavemen out there.” Where the Paleo Diet goes wrong is that it fails to replicate the wide diversity of foods hunter-gatherer societies have historically eaten. At the same time, the strong possibility that those who subscribe to this diet will fail in mimicking the active lifestyles that safeguarded our ancestors from diabetes and heart disease is often downplayed.

What this really comes down to is the notion that no one diet epitomizes the ideal human diet. Rather, one of the wonders of Homo erectus—and this has typically been true of humans today—is that we’ve been able to adapt to our environments throughout time. Adaptation is one thing, but many humans today are currently facing a new sort of dilemma. Touching on the evolution of cooking and what this development has meant for us humans, Gibbons explains how, by cooking our food, our guts get to spend less time trying to break down energy. What this means is that we’re allowed to extract more fuel by doing less work. Unfortunately, many of us have gotten a little too good at this. As Gibbons says, “For the first time in human evolution, many humans are getting more calories than they can burn in a day.” So, where does this leave us? Whether you’re the type of person who needs to have a regimented diet, or someone whose schedule doesn’t allow for much home-cooking, Gibbons leaves us with a succinct message: “If most of the world ate more local fruits and vegetables, a little meat, fish, and some whole grains, and exercised an hour a day, that would be good news for our health—and for the planet.” We will all need to figure out what sort of diet works for us individually, based on our predilections and the various responsibilities we’re faced with on a daily basis, but I would say that this framework certainly seems like a good place to start.

Read more about the "Future of Food" on National Geographic's food channel.

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