While the paleo diet may seem like nothing more than a modern-day fad, one Binghamton University alumnus is studying its roots through the evolution of human teeth.
Peter Ungar, a professor at the University of Arkansas who graduated from BU in 1985 with a B.A. in anthropology, addressed students and faculty Monday night as part of the EvoS lecture series. His research focuses on the evolution of the human diet, and according to him, will help explain humanity’s relationship with the environment.
“Diet is in fact the single most important parameter underlying the behavioral and ecological differences among living primates,” he explained.
Ungar said that tooth size is the simplest way to study the human diet throughout time. According to him, large teeth would be useful to process rough, low quality foods such as vegetation, meaning that in theory herbivores should have large teeth. But in reality, he found that leaf eaters had short jaws and smaller teeth to increase bite efficiency.
But he also said that tooth size alone is not the most telling way to study human ancestors’ diets. Molar enamel thickness, the outer hard surface of the teeth, could say more.
According to Ungar, enamel originally developed for savanna or ground living. The enamel can lengthen the lifespan of the tooth in an abrasive ground environment or strengthen the tooth against breakage from hard brittle foods like nuts, roots, seeds and dried fruits found in an open savanna.
Tooth shape may also be an indicator of diet, Ungar said. Hemispherical, blunt cusps are ideal for hard vegetation foods, while meat eaters required a different design.
“If you’re eating meat, on the other hand, you want to have blades, blades that shear or slice past one another so that they can separate that meat,” he said. “You don’t have to worry about breaking that tooth because the food’s not hard.”
Human ancestors had less specialized teeth, and probably a broader diet that included both savanna and forest resources, likely with more meat.
“Tooth size, shape and structure reflect adaptation to food properties, but it tells us what an animal may eat, not what it eats on a day to day basis,” he said. “If we can understand what animals in the past actually ate, we can compare to what they’re designed to eat, to understand the way evolution works.”
Matthew Rios, a senior majoring in psychology, said the event gave him a new perspective on a topic that was generally discussed differently.
“I thought that it was informative because this article brings to light a very particular issue in paleontology and biological anthropology in that we often try to assume too much behavior from looking at bones alone,” he said.
Ungar’s current research measures microware, the small scratches on the surface of the teeth of fossils. Complex or pitted surfaces indicate the presence of a hard-food diet while simple, uniformed, striated surfaces indicate the presence of tougher foods, like meat.
“Early homo, biological members of our own genus, had increasing variance in microware texture, complexity consistent with a broad diet and a wide range of food fracture properties becoming more so over time,” he said.
Susan Ryan, EvoS program coordinator, said the decision to invite Ungar was a combination of his expertise and the relevance of the paleo diet today, which has made a resurgence.
“He’s writing over 130 scientific journal articles and books on the topic,” Ryan said. “He really knows mammal teeth and molars and the evolution of humans and human ancestors.”