Study: Humans Burn Half The Calories As Other Mammals
ATLANTA (CBS Atlanta) – According to a new study, humans and other primates burn half as many calories each day compared to other mammals.
The study explained that slow metabolisms are the reasons why humans and other primates grow up slowly and live longer lives.
The study also reported that primates in zoos use as much energy as those in the wild.
Most mammals live a fast-paced life. They reach adulthood in a matter of months, can reproduce frequently, and die in their teens. Humans have a childhood made up of many years, reproduce infrequently, and live long lives.
Researchers worked with primates in zoos, sanctuaries, and the wild to examine their daily energy. Over 17 species were studied to see if slow pace of life results from a slow metabolism. The researchers were able to measure the number of calories the primate burned over a 10-day period by a technique called doubly labeled water. Doubly labeled water tracks the body’s production of carbon dioxide.
“The results were a real surprise,” Herman Pontzer, an anthropologist at Hunter College in New York and the lead author of the study, said in a press release. “Humans, chimpanzees, baboons, and other primates expend only half the calories we’d expect for a mammal. To put that in perspective, a human – even someone with a very physically active lifestyle – would need to run a marathon each day just to approach the average daily energy expenditure of a mammal their size.”
The researchers were able to show that a reduction in metabolic rate accounts for their slow pace of life, which indicates that evolution has acted on metabolic rate to shape a primate’s slow life.
“The environmental conditions favoring reduced energy expenditures may hold a key to understanding why primates, including humans, evolved this slower pace of life,” David Raichlen, an anthropologist at University of Arizona and coauthor of the study, said in a press release.
The study was published in the Proceedings of the National Academy of Sciences.