Humans have long struggled to resist meals rich in carbohydrates — commonly referred to as carbs — and this craving is believed to stem from our early ancestors.
For years, it was assumed that early humans primarily consumed a protein-heavy diet to survive the rigors of hunting and evading predators, fostering a deep-seated desire for carbs.
However, according to CNN, a new study published in the journal Science, debunked this long-held belief, suggesting that humanity’s modern-day affinity for carbs may predate the emergence of the Neanderthals.
The study, conducted by researchers at The Jackson Laboratory in Farmington, Connecticut, and the University of Buffalo in New York, points to a specific gene, called AMY1 that enabled humans to digest starches more easily by breaking them down into simple sugars that can be used for energy.
These genes continued to duplicate long before the rise of agriculture.
The team of researchers studied the genomes of 68 ancient humans, focusing on the AMY1 gene and, while almost all modern humans have multiple copies of this gene, the number of copies varies from person to person.
Geneticists have struggled to determine exactly how and when the gene began to expand — which ties back to when eating starches became advantageous to human health.
“The main question that we were trying to answer was, when did this duplication occur? So that’s why we started studying ancient genomes,” Feyza Yilmaz, an associate computational scientist at The Jackson Laboratory, told CNN.
“Previous studies show that there’s a correlation between AMY1 copy numbers and the amount of amylase enzyme that’s released in our saliva. We wanted to understand whether it’s an occurrence that corresponds to the advent of agriculture. This is … a hot question.”
The researchers found that hunter-gatherers as far back as 45,000 years ago had around four to eight copies of AMY1.
This indicates that homo sapiens had a knack for starch even during the Mesolithic period – and before the introduction of agricultural practices.
The research also found duplication of AMY1 in the genomes of Neanderthals and the lesser-known Denisovans — an extinct hominin discovered in 2010.
The multiple copies of the gene in three separate human species indicates that it was a trait shared by a common ancestor before the lineages fractured, according to the study.
That means humans had more than one copy of AMY1 as far back as even 800,000 years ago and the lack of a clear reason for the duplication led researchers to believe it likely happened at random.
AMY1 duplication spiked during the last 4,000 years as humans shifted away from the hunter-gatherer lifestyle toward more starch-forward diets.