You Probably Can't Blame Your Metabolism For Weight Gain

We’ve all heard it before. “It’s not my fault! My metabolism has slowed down!” It’s practically the anthem of anyone over the age of 30 who starts to notice a few extra pounds… every time you step on the scale.

But here’s the thing - your metabolism may not be the culprit. Research now shows that, on average, your metabolism doesn’t slow down as dramatically with age as we once thought.

So, what’s really going on? Let’s touch on a little of the science and then let a few hard truths loose.

Slowing Metabolism - Myth Debunked 

First, let’s debunk the most comforting myth ever created: that your metabolism takes a nosedive the second you celebrate a milestone birthday.

A recent study from 2021 showed that from the age of 20 to 60, your metabolism doesn’t change that much at all (even during pregnancy!) That's right - those extra pounds you’ve blamed on your slowing metabolism might be a little less about your biology and a little more about lifestyle changes. Sure, metabolism can slow down slightly after age 60 - most likely due to having less fat-free mass - but for most of your adult life, it remains pretty steady.

Most experts agree that the biggest changes in metabolic rate happen before age 1 (when you’re growing like a tiny superhuman) and again after age 60 (when you start to lose muscle mass).

Between those milestones? Your metabolism is just hanging out. This means that the gradual weight gain most people experience in their 30s, 40s, and 50s isn’t due to metabolism slowing—it’s due to lifestyle shifts.

According to Dr. Herman Pontzer, the author of Burn: New Research Blows the Lid Off How We Really Burn Calories, Lose Weight, and Stay Healthy, “Most people’s daily energy expenditure, when adjusted for body size and composition, remains quite stable throughout much of their adult life.” In other words, your body is burning energy at the same rate—it’s just that you’re probably giving it more fuel (read: calories) than it actually needs.

Not to say there are not any changes in metabolism in our later years, but these age-related drops in total energy expenditure are more likely related to having less muscle mass, overall lower activity level, and decline in organ-level metabolic rates.

Why the Weight Gain?

The average person gains about five pounds per year, every year. By the time you’re 40, you could be carrying around an extra 50 pounds without realizing it. And guess what? It’s not your metabolism. It’s more likely that it’s your lifestyle. 

Daily activity, exercise, and diet all play a much larger role in your weight than the ticking clock of age.

As we age, we tend to move less. Instead of running around, we’re sitting at desks, driving cars, and chilling on the couch (Netflix, you’re next in line to blame). Plus, after a long day, that nightly indulgence in "just one" glass of wine or a nice bowl of ice cream - okay, maybe two - certainly doesn’t help matters.

Calories in, calories out; if you haven’t heard of it, we’ll cover that in another article. Your metabolism didn’t slow down, but your activity level sure did.

What Can You Do About It?

So, if we can’t blame metabolism, what can we blame? Well, I hate to break it to you, but the answer is…. just you. The culprit behind that extra weight is your diet, your activity level, your lack of intentional exercise, and even the "healthy" snack choices.

These things have a “snowball effect” where they build on each other over time, compounding.

Not to worry, though. You're not doomed (even though you may feel like you are.) The great news is that the solution is entirely within your control.

Start by simply incorporating more physical activity into your daily routine. It doesn't have to be anything extreme - taking a 10 minute walk, taking the stairs instead of the elevator, and standing more often can make a huge difference.

Your body will give you major bonus points if you add strength training to your regimen to maintain and build muscle mass (which burns more calories at rest - think about that one - how awesome is burning calories just existing?).

And of course, your diet, that you are in total control of. Be mindful of portion sizes and the quality of your food choices. What you choose to put in your mouth is 100% up to you…

Take the Blame

Next time you catch yourself blaming your metabolism for weight gain, remember that it’s probably more about your own lifestyle choices than biology. Your metabolism isn’t throwing in the towel; it's been steady for years. Maybe it’s time to take a closer look at your daily habits, activity levels, and food choices.

Keep in mind, you’re not stuck. You’re in control. So, put down that third slice of pizza and go for a walk. Your metabolism will thank you—and so will your future self.