Humans Developed Larger Brains Due To Faster Metabolism, More Body Fat, Study Suggests.

reports in “Speaking of Science” that a study published in Nature indicates humans may have evolved larger brains and lived longer due to a faster metabolism. Researchers “looked at metabolic rates of humans and zoo apes,” and found that “humans had higher energy budgets than any animal other than an adult male gorilla.” According to the researchers, the findings indicate “humans have overcome a biological constraint that holds most other creatures back.” Science Magazine (5/4, Gibbons) reports that the study shows human metabolisms “burn calories 27% faster,” which “equips us to quickly fuel energy-hungry brain cells, sustaining our bigger brains.” In addition, the study “also found that humans are fatter than other primates, giving us energy stores to draw on in lean times.” The authors said the next step in research is to determine how humans were able to boost their metabolisms above those of apes. https://www.washingtonpost.com/news/speaking-of-science/wp/2016/05/04/the-evolutionary-key-to-our-big-brains-and-long-lives-a-faster-metabolism/ What if, instead of sacrificing energy for one organ to pay for another, we just increased our overall budget? So he compared human energy expenditures to those of our closest relatives: chimps, bonobos, gorillas and orangutans. And he believes his hypothesis proved correct: Humans have a basal metabolic rate (the number of kilocalories we burn simply by being) between 200 and 600 calories larger than other apes. The gulf between our total energy expenditure and theirs was even greater — as many as 820 calories. Our ability to use up energy is abnormally high even when you adjust for things like body size and activity levels, Pontzer said.