Metabolism and Aging: We Had It All Wrong
When it comes to what we know about metabolism and weight loss, the conventional wisdom is that the older you get, the easier it is to gain weight because your metabolism starts slowing down from your 20s onward. Women have slower metabolisms than men, and it gets even worse during menopause.
It turns out that all of this may be wrong, according to a paper published in August 2021 in Science. For this study, an international team monitored the energy expenditures of over 6,000 people ranging in age from one week to 95 years old from 29 different countries. Previous studies didn’t have this kind of scope due to cost—to work around that limitation, several labs shared their data, which led to some surprising finds.
Men and women had similar metabolic rates after accounting for body size and muscle mass. Metabolisms did slow over time, but not at the stages we would have expected:
- From birth to one year old, metabolic rate soared—up to 50% higher than it would be during adulthood.
- From one to 20 years old, metabolism decreased almost 3% a year.
- From 20 to 60, metabolism didn't change.
- After age 60, metabolism decreased by 0.7% annually.
One limitation of the study is that the analysis didn’t account for decreases in muscle mass that happen over time—a problem we do know can happen as we age.
So…what does this all mean?
This is GREAT news for those of us who are looking to adopt new habits around fitness, health and nutrition but may have thought it wasn’t worth trying because our metabolisms had already slowed.
For those of us over 60, it turns out our metabolisms haven’t been slowing down since our 20s. If you’re finding it more difficult to lose weight recently, it may because your metabolism is finally slowing down—although not as rapidly as we may have thought. You may need to try some new tactics on how to lose weight after 50.