You remember the moment it hit you: When you realize that, even though you’ve been eating about the same and exercising a fair amount, you’ve put on a few pounds. Or, you came back from vacation only to realize you weren’t bouncing back as quickly as you used to from the fried foods and frozen margaritas (#noregrets). Maybe you’re not entirely sure what’s going on, but you think you have an idea: Your metabolism is slowing down.

Caroline Cederquist, M.D., author of The MD Factor Diet, says that while it’s different for everybody, your metabolism slows down as you age. For most, it starts in your 20s or 30s. For others, it may not happen until your 40s or 50s. Regardless, it’s important to know how your metabolic system works, so you can keep its engines running at full throttle.

Here’s How to Increase Metabolism at Every Decade



In Your 20s On average, this is when most people experience their highest resting metabolic rate (RMR) — aka when your body burns the most calories just by sitting still. “Some of it is based on genetics, but a large part of it has to do with how active you are,” says Cederquist. We tend to have fewer commitments, which frees up time for active movement. Not to mention your body continuously builds bone until you’re about 25, a process which gives your calorie burn a boost. In your late twenties you might start to notice that you can’t eat quite as frivolously as you used to, but for the most part, your body can bounce back quickly with a cleaner diet and regular exercise.