If you think that humans are beautiful as a species, then we have our distant forebears' eating habits to thank for it, according to an article by Eva Botkin-Kowacki for www.csmonitor.com.
A trend in the evolution of man had piqued the interest of scientists for a long time- a decrease in jaws, teeth and faces from previous human ancestors such as during the split from the hominini tribe to the homo genus around 2.8 billion years ago. In particular, Homo Erectus "upright man", a direct ancestor of homo sapiens, had ssignificantlysmaller features (teeth, jaws and faces) than its predecessor, the australopith.
This decrease in facial features baffled scientists. How could the significantly reduced teeth, mouth and jaw size enabled ancient humans to eat enough food to support their large bodies and larger brains?
A recent study might have solved this long-running evolutionary puzzle. According to researches, two factors might have helped the reshaping of early human face to its more manageable and more aesthetically pleasing size today: the introduction of a meat heavy diet and the development and use of tools to break down food into smaller sizes according to the article citing a study done by Katherine D. Zink and Daniel E. Lieberman published in Nature.
Meat Eater
The introduction of meat into our early ancestor's diet is one of the factors that could have set the stage for a reduced need for food quantity. Meat, being an energy-dense food, meant that a lesser volume needs to be processed (chewed) by early hominins to satisfy their body requirements. Researchers estimate that even with a diet that is only one-third meat, early human ancestors needed to chew 13 percent less compared to an entirely plant-based diet.
Use of Tools
Using tools for slicing meat into smaller pieces as well as pounding vegetables would also dramatically decreased chewing and masticating needed by early human ancestors to digest their food. This was tested by the researchers by designing a test to see how much chewing difference is needed to effectively masticate sliced meat as opposed to unsliced meat and also for pounded vegetables compared to unpounded ones. The results show that cutting meat and slicing vegetable effectively reduced the number of times the subjects had to chew before swallowing.
Combining the two factors, the one-third meat diet and the tools to cut meat and pound vegetables, the researchers were able to compute that ancient human ancestors need to chew 17 percent less frequently and 26 percent less forcefully.
Study author Katherine Zink explains that these changes in eating might be small but they have drastic cumulative effects over the thousands of years of evolution.
This explanation of how humans got smaller teeth and jaw is supported by George Washington University paleoanthropologist Bernard Wood according to Botkin-Kowacki's article. Although not part of the study, Wood explains that evolutionary changes tend to steer toward efficiency which according to him, "you don't want to develop anything that's larger than you really need."
It is amazing to think how such minor dietary change can have such far-reaching effects over the years. It certainly makes one think where this recent but more drastic nutritional change - the introduction of ultra-processed food in modern human's diet - could lead the species in future evolutionary paths. Can it be theorized that humans might look even better in the future by eating junk foods? It could be possible but perhaps a safer bet would be a shorter lifespan.
