Humans have evolved an exceptionally high metabolic rate, unlike any other known animal. Unlike primates that conserve energy by being less active, humans can stay on the move thanks to sweating, which prevents overheating. This metabolic advantage may have been key to our evolutionary success.
Humans have significantly higher metabolic rates than other mammals, including our closest relatives—apes and chimpanzees—according to a new Harvard study. Researchers suggest that having both a high resting metabolism and an active one allowed our hunter-gatherer ancestors to gather enough food while also supporting larger brains, longer lifespans, and higher reproduction rates.
“Humans are off-the-charts different from any creature that we know of so far in terms of how we use energy,” said study co-author and paleoanthropologist Daniel Lieberman, the Edwin M. Lerner Professor of Biological Sciences in the Department of Human Evolutionary Biology.
The Energy Puzzle: How We Burn Calories Differently
Published in the Proceedings of the National Academy of Sciences, the study challenges the long-held belief that human and non-human primates have similar or even lower metabolic rates than expected for their body size.
Using a refined comparison method that accounts for body size, environmental temperature, and body fat, the researchers found that humans, unlike most mammals—including other primates—have evolved in a way that avoids the typical tradeoff between resting and active metabolism.
Why Chimps Are Couch Potatoes and Humans Keep Moving
Animals take in calories through food and, like a bank account, spend them on expenses mostly divided between two broad metabolic categories: resting and physical activity. In other primates, there is a distinct tradeoff between resting and active metabolic rates, which helps explain why chimpanzees, with their large brains, costly reproductive strategies, and lifespans, and thus high resting metabolisms, are “couch potatoes” who spend much of their day eating, said Lieberman.
Generally, the energy animals spend on metabolism ends up as heat, which is hard to dissipate in warm environments. Because of this tradeoff, animals such as chimpanzees who spend a great deal of energy on their resting metabolism and also inhabit warm, tropical environments, have to have low activity levels.
The Secret Weapon: Sweating for More Energy
“Humans have increased not only our resting metabolisms beyond what even chimpanzees and monkeys have, but — thanks to our unique ability to dump heat by sweating — we’ve also been able to increase our physical activity levels without lowering our resting metabolic rates,” said co-author Andrew Yegian, a senior researcher in Lieberman’s lab.
“The result is that we are an energetically unique species.”
“Humans have increased not only our resting metabolisms beyond what even chimpanzees and monkeys have, but — thanks to our unique ability to dump heat by sweating — we’ve also been able to increase our physical activity levels without lowering our resting metabolic rates.”
Andrew Yegian
How Our Bodies Became Metabolic Powerhouses
The team’s analysis shows that monkeys and apes evolved to invest about 30 to 50 percent more calories in their resting metabolic rates than other mammals of the same size, and that humans have taken this to a further extreme, investing 60 percent more calories than similar-sized mammals.
“We started off questioning if it was possible that humans and other primates could have comparatively low total metabolic rates, which other researchers had proposed,” Yegian said. “We tried to come up with a better way to analyze it using quotients. That’s when we hit the accelerator.”
What’s Next? Studying Metabolism in the Modern World
The research team — which includes collaborators at Louisiana’s Pennington Biomedical Research Center and the University of Kiel in Germany — plans to further investigate metabolic differences among human populations. For example, subsistence farmers who grow all the food they eat without the help of machines have significantly higher physical activity levels than both hunter-gatherers and people in industrial environments like Americans. However, all human populations, regardless of activity levels, spend similar amounts of energy for their body size on their resting metabolic rates.
“What we’re really interested in is variation among humans in metabolic rates, especially in today’s world of increasing technology and lower levels of physical activity,” said Yegian. “Since we evolved to be active, how does having a desk job change our metabolism in ways that affect health?”
Reference: “Metabolic scaling, energy allocation tradeoffs, and the evolution of humans’ unique metabolism” by Andrew K. Yegian, Steven B. Heymsfield, Eric R. Castillo, Manfred J. Müller, Leanne M. Redman and Daniel E. Lieberman, 18 November 2024, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2409674121
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38 Comments
The blind who refuse to see design when it is right in front of them.
You know, I’m prepared to see the design, but I’m having issues with the designer.
We have known about evolution, as the article expands on, for almost two centuries.
If my metabolism is so high then why am I so fat???
It’s the diet. Switch to ketosis and see it melt. Sugar and carbs trigger inflammation and make you puffy and fat.
Better yet, don’t do ‘health’ fads since they can be unhealthy, Eat and move with variation, as your nation’s health service will advise you.
All mammals sweat except the domestic pigs
This is how Jesus, God, Holy Spirit, made our body’s. What I can’t believe that people wasted all the time, energy, money, to say that we sweat and it cools our bodys. It is like when all the money was wasted going to the moon to find out that the moon has reflective rocks that reflect the light of the sun, just like the Bible says, a light by night.
Please keep your superstition to yourself on a site where the rest of us expect to read and discuss facts about the natural processes (here evolution).
incorrect
Superstition is believing something came from nothing and nothing was activated by something…….. Yeah your superstitions…… good grief grow up and learn some manners. Obviously your parents never taught you.
Yes, it has evolutionary ancestry. But it is not generally used for cooling.
“Although sweating is found in a wide variety of mammals,[6][7] relatively few (apart from humans, horses, some primates and some bovidae) produce sweat in order to cool down.[8] “
Dogs don’t sweat either… they also mentioned other primates do no not sweat also.
Pigs are the only mammals that don’t have sweat glands
Dogs and cars don’t sweat, at least not from all over their skin. Horses do sweat…their coat gets wet from sweat when they exert themselves.
The ignorant that can’t comprehend the power of natural selection when it’s right in front of them.
Natural selection, is this why there is more cancers, viruses, and diseases in the world now and more people are being born with disabilities. Greed, the lust of the eyes, the lust of the flesh, the pride of life. People refuse to repent and turn to the Lord.
I’d argue that there’s no one close to the Lord than the current Pope. Yet he’s there now, lying in bed with double pneumonia.
Evolution is a neutral natural process, and we expect it to produce “Nature, red in tooth and claw”. It is the superstitious myths you refer to that propose atrocities.
What peculiar comments. Why read this rag if you are a creationist. Also I think the point is humans sweat a lot more than other animals to cool down.
Goodness gracious golly gee wil-a-kers! Looks like a zealot raid is in progress. Those who proselytize with such fervor, have you considered this: God made each one of us just the way we are. Sure we have free will, but we are still the result of Devine creation. So to denounce our fellow man is indeed to denounce God. Rather than squabble in filth and mud, let us carry each other up. Let us know ourselves and thus know our neighbors. The ultimate trial presented in our lives is can we accept and love others? Can we realize our own pride and be humble in front of adversaries? Can we extend the hand of love and respect to those with whom we share no commonality?
Indeed, Sygil, let us not “squabble in filth and mud, let us carry each other up.” You have spoken truth.
The answer to your questions is a simple, “No.” Vide Warsaw before 1939, Palestine before 1948, the Philistines, and Moses.
If you are a creationist why get onto a page about scientific research and speak foolishness to people that belive with their eyes rather than their “soul”, if you want to understand why something happens then look to science, if you want to be told a fairytale from a book go to church, the fact is the church believed that the ground we stand on is flat, until scientists proved otherwise so any religious nut want to tell me why the hell the pope’s so good when he has his way with children, but scientists are bad because they tell truth?? Anyone willing to touch the subject, any person who believes a book called the holy Bible is a fool, its been written by man, as it says in that book can’t be trusted to be honest, so remember that science is for knowledge religion is for the sheep to follow, BTW this is the most believable explanation about mammals, thinking that religion has tarnished any possibility otherwise is ridiculous, all religion came from one thing and that is a story passed to one another, does anyone know what that means??? It means it changed over and over, thanks folks for understanding this rant, if you don’t understand it go talk to your holy Bible maybe you will get your answers, ill keep asking questions and learning, rather than praying for an answer and never getting it.
I can’t understand the idea of popagating opinions involving immoral superstitions on a science site, no. They can take it elsewhere.
Don’t you know that Natural Selection shows conclusively that “design” in nature is a nonsense?
And who made god, and does he sweat?
For everyone that’s not a religious nut, this has been known for like the last 12 years. No idea why a paper analyzing metabolic rates is pretending we didn’t know the absolute powerhouse that is sweat. For Christ’s sake there are infotainment specials from the 80s that bring up sweats role in our evolution.
‘sweat’s’ or ‘sweats’? Big difference in this context.
*aside* – did apostrophes evolve or were they created?
I am afraid that I fail to understand why some of the people that have responded to this article why they have even bothered to read articles such as this especially wearing the blinking that they do.
Do me a favour and please read the bible and extract proof that there is such a thing as design intervention.
Remember that it was written over 2000 years ago by people who did not know much more than people like you, try writing that book today.
By the way I am still waiting for something that you people predict is going to happen actually happen.
Remember that these type of arthritis are about science not what you choose to believe if you want to complain do so about the science and prove so otherwise
T-bone, you haven’t added anything to this conversation by nitpicking spelling and punctuation. You make yourself look worse instead of better when you do such things. Be a better person. I will not return to see any of your responses to this.
The new here was the observation of the metabolic rates, which supports hypotheses on the role of sweat cooling.
If y’all truly read those big books from the very beginning you’d know full well they are a declaration of independence.
And if you truly believed that God is everything everywhere then you would study as much as possible in order to better understand it.
You can clearly see evolution and human adaptation and how it is influenced by its environment eg Africa which is a relatively flat continent due to very little active plate tectonics. Roaming the large savannas where humans evolved to need extra caloric expenditures how fascinating. Makes sense why Africans have so much stamina and win at track and field.
Then what made your god and how do you know your god is the correct one out of the 4000+ gods? We see the facts of evolution every day but for some reason never a God unless we lie and grab information from a book called the bible that has over 80,000 versions.
It’s the God being taught the most that said He will be taught the most. It’s the God that doesn’t sound like he was just written out of the mind of man (saying they themselves will be turned into gods and have a bunch of super powers, spouses, and planets. Some even say they will be turn into animals or things like water or trees). It’s the God that says we don’t just end here, but will one day go into our next phase of existence with a new updated body when this form stops working.
The ironic part is. Even science says one animal evolving good traits should take longer than the sun’s life.. as test after test they see that genetic info is only lost and doesn’t get more complex like evolution requires.
Even the evolution thing they claim is real is forced parasitism as humans needed tool to make two single celled things get together that they specifically picked out….
And also funny as ligers show that our ancestors that are further separated from theirs than lions and Tigers are. How’d our ancestors mayevas chimera offspring are sterile 100% of the time.
Each human sub group too far apart to even do that. But scince ignores that and their other test shows other cells they chose, dying and getting less complex over time like they always have… how’d they bottleneck then and get more genetic info after in different group of lifeforms.
Science couldn’t even try to fake Lucy to. Used tools on the bones to get rid of parts that show she never walked like us at all. But on all fours and didn’t even find 10% of her actual bones. Created their own based on assumptions.
K8nda funny theyvstill di yhd hunsn test thing ad they admitted catches are basically useless tools for spying and don’t even stop bots. In fact the use them ti train a.i on identifying things. It’s very purpose of stopping vots, it literally is used to help better be able to not tell… on purpose. But yeah keep asking if we’re human and spying on our stuff through it. Like I want some random site seeing screen inputs as that’s not all it can do is it…