Reviewed By Danielle Glesne, RDN, LD, CDCES

The short answer is yes—BUT, likely not in the way you think.

A lot of us remember a time when we could seemingly eat anything we wanted and not gain weight.

A lot of us also remember the time it seemingly changed dramatically—whether that was in our 20s, 30s, or 40s.

“Your metabolism slowed” is what we were told, what we believed, and what we repeated to others.

Our perception, however, doesn’t match reality.

Metabolism Over Time

A fascinating new study entitled Daily Energy Expenditure Through the Human Life Course (PMID: 34385400) has shown our metabolism actually peaks much earlier in life than we tend to believe, and starts its slow but inevitable decline much later in life than we tend to believe.

SUMMARY FINDINGS

• Energy needs rise rapidly during the first 12 months of life, such that by their first birthday, a 1-year-old burns calories 50% faster than an adult relative to body size.

• After this initial surge in infancy, metabolism slows by about 3% each year until we reach our 20s.

• During the next 40 years, from our 20s to our 60s, our metabolism remains steady—even during pregnancy.

• After the age of 60, our metabolism begins a gradual slowdown, to the tune of only 0.7% per year.

• The study also found this pattern holds even when taking into account varying levels of activity.

More concisely: Human metabolism rises from birth to age 1; slows from ages 1-20; holds steady from ages 20-60; and gradually declines after 60.

Here’s the data in visual form…

For a good summary article on the study, read: Study Suggests That Yes, Metabolism Does Start to Slow over a Lifespan, but Perhaps Not When We Might Think

what Does This Mean?

Practically, this means a few things:

• Your metabolism isn’t “broken,” it’s continuously adapting.

• Your metabolism wasn’t “on fire” in high school, it was highest when you were 12 months old and then slowed gradually until you were about 20 years old.

• Excess weight gain in adulthood is not due to a slowdown in metabolism.

The good news: Nutrition is still the greatest determining factor of body composition—and you can control that.

For more on the relationship between nutrition and metabolism, read my article: 7 Ways to Increase Your Metabolism with Nutrition

Questions?

As always, if you could use guidance on what’s right for your individual context and goals, please don’t hesitate to CONTACT US.

We’re here to help.