The average person gains one to two pounds every year, starting in early adulthood. Many things contribute to this phenomenon, but it’s long been “common sense” that it’s partly because our metabolism slows as we age.
Recent research paints a very different picture. In fact, it appears to be the case that metabolism is highest between birth and age one, decreases slightly each year from ages one to 20 and then stays constant until age 60. Even after age 60, it slows only 0.7 percent per year.
These findings, the result of cooperative work between Duke University anthropologist Herman Pontzer and more than 80 co-authors, were published last year in the journal Science. The scientists looked at the average calories burned by nearly 7,000 people in 29 countries. Subjects ranged in age from one week to 95 years.
Constant metabolic rate between ages 20 and 60 wasn’t the only surprising thing the researchers found. Contrary to conventional wisdom, metabolic rates did not differ between men and women, and were not affected by pregnancy or menopause.
“There’s nothing sort of more fundamental and basic than how our bodies burn energy, because that represents how all our cells are busy all day doing their various tasks, and we didn’t have a good sense of how that changes over the course of a lifespan,” Pontzer told NBC News.
According to Pontzer, there’s no proven way to speed up metabolism, and weight can be affected by many factors, including activity level, sleep patterns and stress. Exercise and diet won’t change metabolism, he says, but they do have significant benefits.
“You’re burning a set number of calories each day, but you get to decide how to burn them,” says Pontzer. “If you expend them on exercise, you’re going to be a lot healthier and have less inflammation than someone who doesn’t. The same is true with food. You decide how to fuel your body. That’s where a healthy diet factors in.”
Many resources are available on the eSavvyHealth website to help you make informed choices about diet, based on your understanding of basic concepts of metabolism. These include free eBooks and short video courses. To see them, click here.
