How an ancestral shift to eating more meat changed the course of human history — for the better

It helped us reach our “prime.”

The Progression of Man apparently wasn’t as gradual as once thought. UK researchers found that our ancestors experienced a rapid growth spurt between 2 and 2.5 million years ago, potentially due to increased meat consumption and walking upright, per a beefy study published in the Proceedings Of The National Academy of Sciences.

The authors set out to shed light on the size discrepancy between modern humans, whose average weight clocks in at 137 pounds globally, and our earliest prehistoric forebears, such as Australopithecus, which weighed a child-sized 88 pounds on average.

They specifically wanted to know if this evolutionary pound-packing happened incrementally over time or in rapid spurts like prehistoric puberty, IFL Science reported.

“For years, different studies have come to different conclusions about whether our ancestors steadily grew bigger over time or jumped in size at some key point,” said lead author Jacob Gardner at the University of Reading.

He believes that by analyzing the various theories, piecing together the fossils and comparing the different species, they were able to paint the complete picture.

To get to the bottom of how our species reached new heights (and weights), the researchers specifically analyzed 386 specimens of hominin encompassing 21 species, from Australopithecus to modern humans.

They then ran a series of 1,000 statistical models to measure how body size changed over millions of years, accounting for structural family-tree relationships and historical gaps.

This improved upon prior scholarship, which either focused on the growth trajectory of specific species, Australopithecus or later forms of Homo, and tried to extrapolate sizes from incomplete fossils.

By combining all the methods, the researchers discovered that these fragmentary models weren’t at odds with each other, but rather focused on a narrow sample size.

According to the new comprehensive research, body weight steadily increased over time in our earlier hominin ancestors, like Australopithecus — the 90-pound weakling — before experiencing the 50-pound jump during the emergence of Homo erectus and Homo ergaster circa 2 million years ago.

These species walked on two legs more efficiently, ate more animal protein, and covered greater distances in search of food, Neuroscience News reported.

In turn, this larger physique allegedly enhanced the efficiency of bipedal movement, allowed us to travel greater distances while expending less energy, and increased our ability to hunt or scavenge meat and fend off predators — important milestones in human evolution.

“This change coincided with broader developments in how our ancestors moved across landscapes and exploited their environments, pointing to a close relationship between body size and major ecological and behavioral transitions,” said co-author Dr Thomas Puschel, of the School of Anthropology and Museum Ethnography, University of Oxford.

In other words, meat literally helped us grow as a species.

Coincidentally, not all hominins followed this “meatier” growth trajectory.

While Homo erectus attained modern weights, other lines such as Homo floresiensis — nicknamed “Hobbits” after the fun-sized protagonists of the “Lord Of The Rings” series — retained a child-like stature.

“The human story is not simply one of constant growth, but also of a major change that happened later, within our own genus, while other branches of the family, including some surprisingly small relatives, went their own way entirely,” said Gardner.