Say aaaaaah! Dental caries and other signs of oral disease are plain to see in the upper teeth of this hunter-gatherer, between 14,000 and 15,000 years old. The findings challenge the idea that the original paleo diet was inherently healthy, says paleo-anthropologist Louise Humphrey. It all depended, she says, on what wild foods were available. Courtesy of Isabelle De Groote hide caption

itoggle caption Courtesy of Isabelle De Groote

Nom Nom Nom: From left, a cast of teeth from a chimpanzee, Australopithecus afarensis and a modern human. We switched from an ape-like diet of fruits and leaves about 3.5 million years ago, according to fresh research. There's evidence that meat-eating came about a million years or so later. William Kimbel/Institute of Human Origins hide caption

itoggle caption William Kimbel/Institute of Human Origins

A 3-D reconstruction of Mummy 38's CT scans shows calcification in her aorta and iliac arteries. Courtesy of The Lancet hide caption

itoggle caption Courtesy of The Lancet

Some of The Salt's most popular posts of 2012 included coffee, pink slime and Downton Abbey. Daniel Acker/Landov; Carnival Film & Television Limited 2011/Masterpiece; Adam Cole/NPR; Robyn Mackenzie/iStockphoto.com; Lass/Getty Images hide caption

itoggle caption Daniel Acker/Landov; Carnival Film & Television Limited 2011/Masterpiece; Adam Cole/NPR; Robyn Mackenzie/iStockphoto.com; Lass/Getty Images

Members of the online community Track Your Plaque get advice from a doctor and each other on how to cook low carb meals. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Vlad Averbukh, 29, a follower of the paleo diet, eats raw meat along the Hudson River in New York in 2010. (Averbukh did not weigh in on our blog post on the paleo diet.) Emmanuel Dunand/AFP/Getty Images hide caption

itoggle caption Emmanuel Dunand/AFP/Getty Images