How much does metabolism REALLY slow down with age?

This our client. He is jacked. And shredded. He has a six-pack. And he's 50. Is it all thanks to a fast metabolism?

It’s widely believed, by pretty much everyone I’ve ever talked to at least, that our metabolism slows waaaayyyy down as we get older. You may have heard someone say it, or even believe it yourself - most people do!

You certainly wouldn’t be the only one to think this is true, and you’re not imagining things - you may have noticed that once you reached a certain age, some things about your body changed in inconvenient ways, i.e. easier weight gain than before, and you figure that your naturally declining metabolism must be to blame. Everyone talks (or, rather, commiserates) about it so it must be true, right?

No matter the age at which we start to notice these changes, most people have experienced some version of feeling like they’re gaining fat more easily than at earlier times in life, and attribute it to a supposed natural decline in metabolism.

Perhaps gone are the days when you could “eat whatever you wanted and not gain weight,” or now that you’re past a certain age you “just look at a piece of cake and get fat”… I hear these phrases from clients all the time, and then almost inevitably in the next sentence metabolism gets pinned as the villain.

Brace yourself friends, because what I’m about to say might bum you out a little - but only for a minute.

Although some apparent changes in your body might sneak up on you and hit you like a ton of bricks, your metabolism itself isn’t really to blame - it’s more about habits than biology!

This might sound pretty crummy to a lot of us, because I don’t know about you but I’d way rather think that I’d been dealt a shitty hand by nature than acknowledge that it was because of my own action patterns (or lack thereof) that things have gone south…

Of course, there are going to be some people out there with hormonal imbalances, endocrine issues, etc. that may complicate the situation, but for most of us with otherwise relatively normal health profiles, purely getting older doesn’t actually cause your metabolism to slow to a screeching halt.

However, the truly good news is that because whatever seemingly age- and metabolism-related weight gain you may have experienced isn’t all because of biological fate, you have a lot more control over the situation than you might think!

What people typically perceive as they age is that they’re eating the same foods they always did, but now seem to store more of those calories as body fat. Sound familiar?

I’m actually sort of happy to say that this is really due to decreased TDEE, or Total Daily Energy Expenditure, which is the sum of the calories your body burns due to performing regular body sustaining functions (BMR or basal metabolic rate), the exercise you engage in, as well as non-exercise activity thermogenesis (NEAT - or the calories you burn just doing regular life activities separate from your workouts) and other contributing factors.

Ok, so to be fair, your metabolism can decrease over time. HOWEVER, it doesn’t take the crazy, pronounced downhill roll that everyone thinks it does.

In truth, and this is worst case scenario, it only very gradually slows down around a couple of percentage points per decade. Per DECADE. Around 1-2% or so, slowly, over the course of TEN YEARS. That is a long, long time. And a small, small amount.

So, let’s put this in perspective. Let’s say you changed nothing at all about your routine as you aged - you ate the exact same amount of the exact same foods, exercised the same way for the same duration, and moved around just as much. Over the course of ten years your metabolism might decrease at most around 2%. This means that if you needed 2500 calories per day to maintain your weight as a 25 year old and you changed NOTHING about your life routines as I just mentioned, you would need 2,450 calories to maintain your weight as a 35 year old. That means you’d have to eat 50 fewer calories per day in order to not gain any weight. 50 calories is about one piece of light string cheese, 7 almonds, or 1/3 of a small apple that you'd have to forfeit. Not that big of a deal.

The thing I’ve noticed is, lots of publications (magazines and the like, even those with the word “health” in the name) tend to overstate this occurrence, asserting that your metabolism starts to quickly plummet as you progress through adulthood… Even though I’d love to think that nature was behind what most of us interpret as a now “sluggish metabolism,” let’s examine the other factors at work here.

Maybe you remember when you were in high school or college, and you ate whatever you wanted and never gained a pound. Ahhh, the good old days. How wonderful to be young! What you might not also remember though, is that at that time you may not have had a desk job, spent hours sitting down as you commute to work, or spent your evenings on the couch with a bottle of wine or collapsing in exhaustion after putting the kids to bed, putting off your workout until “tomorrow.” You were probably cruising around all day, with plenty of time for yourself, playing sports perhaps, galavanting around with your friends or traversing a giant college campus on foot.

Whatever your circumstances may have been, the point I’m looking to make here is that most of see a huge decline not in our metabolism per se, but in our activity level as we age. Not just purely exercise-related calorie burn, but additional calories burned during daily activities as well, referred to as NEAT (non-exercise activity thermogenesis) as I mentioned before. As we get older, we have a tendency to move around less because of lots of factors, and that adds up! Even habitual exercisers feel these effects because their daily lives demand less activity than they did when they were younger.

What also happens in conjunction with this decrease in physical activity is that we don’t change our eating habits enough, or at all, to compensate for the decreased caloric expenditure we experience thanks primarily to our lifestyles.

Especially if our activity level decreases gradually over time, and since pounds creep on slowly, we may not even notice that these are the causes - we wake up one day 15 pounds overweight and wonder what the hell happened to us. This is not uncommon at all, and is a big reason why the true culprits (decreased daily activity and caloric surplus) behind age-related weight gain can be harder to pinpoint and it’s so tempting to point the finger at nature’s supposed unkindness.

I’m pretty sure I’ve addressed this before in my posts but it bears repeating - I think that misconceptions are widespread regarding the caloric content of food and the caloric cost of exercise, meaning that it’s common to underestimate the number of calories in the foods we eat while simultaneously overestimating the amount of calories we burn through exercise. As we age and our life patterns change, keeping a pretty close eye on these things (even measuring) can help to keep weight gain in check.

Knowing all of this provides a good incentive to begin working out or continue with your routine, incorporating both strength training and cardiovascular exercise into your daily life. Muscle burns a few extra calories for you each day at rest because it takes energy to sustain, and while it may not be a mind-blowing amount, every little bit helps! Also, the small effect of EPOC (excess post-exercise oxygen consumption) adds a couple calories to your daily burn too, so you might as well capitalize on that while you’re at it!

It’s not fate. You’re not doomed. You don’t have to curse your ancestors for gifting you shitty genetics. Instead, take control! Know that you’re in command of your body’s shape, composition, and capability. It will take some effort, and will take a teeny tiny amount more effort each decade, but don’t tell yourself that it’s out of your hands - because it’s not.

Again, this is actually GREAT news if you think of it that way! So, most likely, your metabolism is just fine - you just need to get moving and start thinking about your nutrition a little more carefully because your lifestyle probably can’t support what it once did, when you had more time, more energy, and more freedom to move!

So, let’s get excited about this together! After we get over the initial sting of realizing that we are more in control than we thought, let’s embrace the challenge of owning our health and fitness and making both of them the best they can be!

Need some help with an exercise plan? Got some nutrition questions? I’d love to help!

Please feel free to comment, upvote, or resteem if you found this helpful or interesting! :)