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Why Humans Have Bigger Brains

Body fat, metabolism give people an evolutionary edge over other primates, study finds

WEDNESDAY, May 4, 2016 (HealthDay News) -- Scientists say they've uncovered why humans have such big brains.

It turns out that metabolism -- the rate at which a body burns calories -- runs faster in humans than it does in other primates. And humans have more body fat, which provides the energy reserves needed to fuel that faster metabolism, the researchers said.

What does all of this mean? Greater growth and development of the brain, the researchers said.

In their study, the scientists compared 141 humans to 27 chimpanzees, 11 orangutans, 10 gorillas and eight bonobos -- pygmy chimpanzees. When adjusted for body size, people consume 400 more calories a day than chimpanzees and bonobos, 635 more calories than gorillas and 820 more calories than orangutans.

"Humans exhibit an evolved predisposition to deposit fat whereas other hominoids remain relatively lean, even in captivity where activity levels are modest," researchers from Loyola University in Chicago, said in a university news release.

The team, led by Amy Luke, Lara Dugas and Ramon Durazo-Arvizu, believes the findings could one day help fight obesity.

"Untangling the evolutionary pressures and physiological mechanisms shaping the diversity of metabolic strategies among living hominoids may aid efforts to promote and repair metabolic health for humans in industrialized populations and apes in captivity," the study authors wrote.

The study was published May 4 in the journal Nature.

More information

The U.S. National Institutes of Health has more about minding your metabolism.

SOURCE: Loyola University Health System, news release, May 4, 2016

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