What you think you know about metabolism is completely wrong

Chances are you think of your metabolism as a fire that flares up when you exercise to burn calories. But that’s only a very small fraction of what it does, according to Herman Pontzer, Ph.D., an evolutionary anthropologist at Duke University, author of Burn (Buy It, $ 20, amazon.com), and the lead investigator of a new metabolic study that changes the game.

“Metabolism is the work your cells do every minute of every day,” Pontzer says. “You have 37 million of them, and each cell is like a small factory that secretes everything you need to keep your body going.” Some calories are burned during exercise, but most of what you eat is used to nourish the continuous work your cells perform.

The new research, published in Science by Pontzer and more than 80 co-authors, looked at the metabolism more accurately than ever before. It measured metabolism in nearly 6,500 people around the world, from newborns to 95-year-olds. When the researchers checked for variables that affect energy consumption, such as a person’s body size and fat percentage, they were given “a clear driving license of metabolism over our lifetime,” Pontzer says. Here’s what it means for you.



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Your metabolism does not decrease significantly as you get older

For years, you have heard that your metabolism peaks when you are a teenager and decreases significantly as you approach middle age. But the researchers discovered that metabolism comes much earlier and decreases much later, and that it has four different stages. From infant to 1 year, the metabolism is at its highest and a baby’s metabolism is 50 percent higher than that of an adult. From the age of 1 to 20, the metabolism decreases by about 3 percent per year. So from 20 to 60 years the metabolism keeps stable. After 60 years, it begins to decline slowly (0.7 percent per year). That means you burn calories at a steady rate for 40 years, about 2,500 a day on average, Pontzer says. And a 60-year-old has the same metabolism as a 20-year-old. (Related: Use This Diet To Adjust Your Nutrition To Your Age)

Sex does not affect metabolism

“There’s nothing special about male metabolism,” says Pontzer. “Men tend to be bigger and their bodies are made up of leaner muscles and less fat.” Muscle uses more energy than fat, which is the reason for the difference (the reason why men may be able to lose a pound faster than women). The researchers checked for these factors and found no difference in metabolism.

Pregnancy and menopause do not slow you down

“These major metabolic milestones did not affect metabolism,” said Jennifer Rood, Ph.D., a co-author of the study, who specializes in metabolism and energy consumption research at the Pennington Biomedical Research Center at Louisiana State University. “It was a surprise. But it’s also encouraging. The fact that your rate remains stable through birth and into your 60s means you do not have to work harder to maintain a healthy weight as long as you follow a healthy diet and get the recommended amount of exercise and rest. “

Muscle mass matters

The types of cells you have affect the amount of work they perform and the energy they burn, Pontzer says. “A cell in your fat is not as busy as a cell in your muscles,” he says. “If you have very lean mass, you will burn calories more efficiently than someone who has more fat mass.” This is why training, especially muscle building strength training, can be beneficial.

So can you increase your metabolism?

First reality check: There is no documented way to increase metabolism, says Pontzer. Exercise may push it up a bit, but your daily energy consumption is the same, the study found. Metabolism remains stable.

But exercise and diet do make a difference. “Think of it this way: You burn a certain number of calories every day, but you decide how you burn them,” Pontzer says. “If you use them on exercise, you will be much healthier and have less inflammation than someone who does not. The same is true with food. You decide for yourself how to burn your body. This is where a healthy diet come into play. .”


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