WIKIMEDIA, MICHAEL C BERCHAlthough cooking only took off around 500,000 years ago, human use of tools to process food is thought to have been widespread much earlier. Now, a study from researchers at Harvard University suggests that food processing was key in hominid evolution as a means to increase energy intake while reducing energy expenditure. The findings were published in Nature on Wednesday (March 9).
“By processing food, especially meat, before eating it, humans not only decrease the effort needed to chew it, but also chew it much more effectively,” said study coauthor Katie Zink of Harvard University in a statement. “Using stone tools to process food apparently made possible key reductions in the jaws, teeth and chewing muscles that occurred during human evolution.”
Zink and her colleagues attached sensors to the faces of volunteers to record muscle contractions during chewing. The researchers then fed participants goat meat or root vegetables like yams and beets, that were either raw or had been processed by slicing, pounding, or cooking. After chewing as long as seemed necessary for swallowing, each participant spat out the food for analysis.
“What we found was that ...
