08: is my metabolism slowing down?
i get this question often and in simple terms, no, your metabolism in itself is not slowing down. it’s a little more complex than that though so let’s break it down.
first, let’s clarify what we’re referring to when we say “metabolism”. metabolism can be generally defined as, all chemical reactions in the body that either produce or consume energy. we, along with every other organism on earth, survive by taking nutrients and substances as building blocks for movement, growth, reproduction and development (if you’re curious about the steps of cellular metabolism I added an explanation below). but i have a feeling that’s not the type of metabolism you’re referring to.
you’re most likely referring to the annoyance of gaining weight, mostly fat, as you age regardless of how many calories you eat. generally speaking, a “faster metabolism” means you burn more calories at rest so you can eat more and not gain weight. so if you’re eating the same amount of calories and now gaining weight then your metabolism must be slowing down, right? does this sound familiar?
when I was younger i could eat anything and not gain weight, now I’m older and i eat the same amount and gain weight, the issue must be my metabolism!
unfortunately when dealing with the body, correlation is not always causation. there’s a lot more that goes into how your body breaks down and uses or stores the food you eat. I’ll keep it simple to only what you need to know and how to course correct this yourself.
first, you should know what your basal metabolic rate is or BMR. this is the amount of calories you burn at rest to carry out basic life functions like breathing or blood circulation. Imagine you lie in bed all day and don’t move a muscle, your bmr is the number of calories you’ll need to consume to just lie there. you should always aim to eat above this many calories per day —do not eat less then this to lose weight. doing so will undoubtedly result in poor health and possible negative long term health complications. You can find your BMR number through the use of a body composition analysis machine, i happen to have one of those body composition machines in my studio, all of my clients use this quarterly to monitor progress. You can also book a drop in session to get a reading and I’ll discuss your results with you as well if you’d like, reach out to learn more.
second, it’s well understood that as you age your muscle mass declines. this is significant because your bmr is highly correlated to the amount of muscle mass you have on your frame. more muscle mass, higher bmr; less muscle mass, lower bmr. this is because muscle tissue is metabolically active —meaning it requires energy to maintain— unlike fat tissue. when you have less muscle mass globally, you generally have a higher ratio of fat mass and thus as you age and your muscle mass declines so does your bmr; which is why it can be harder for some to maintain a healthy weight later in life. the best way to stagnate this decline is first, strength train when you’re young. if you’re at higher levels of relative muscle mass when you’re young the decline as you age won’t be so dramatic thus the drop in bmr won’t be as pronounced. second, if you’re a little older, start on a strength training routine as soon as possible. research shows you’re never too late to reap the benefits of strength training but starting young is always the best option. Just make sure you consult a professional to ensure you’re working out in a way that’s right for you and that mitigates your risk of injury.
also, it’s important to note that when I say “increase your muscle mass” i’m not talking about becoming the next Mr. or ms. olympia. strength and muscle mass is relative to each person. you can have a high level of strength and muscle mass relative to you without getting that “bulky” look.
lastly, when it comes to macros let’s keep it simple:
Never eat less than your bmr
exercise has a small effect on daily energy expenditure so don’t aim for calorie burn during workouts
find little ways to move throughout the day, this will increase your non-exercise activity thermogenesis. the best way to explain this is research found those who are more twitchy (bouncing their leg when they sit) burn more calories at rest —just move as often as you can.
if you want to lose weight start with a modest calorie deficit (accounting for bmr, neat, tef, and eat —you can get these numbers in a body composition analysis like i mentioned above). start with a 200 calorie deficit per day for at least two weeks to a month, if you lose less than half a pound of body weight in that time then you can increase to 250-300 calories and try again. do not go above 500 calorie deficit and if you lose between half a pound to 2 pounds per month you’re good, stay there. a greater deficit doesn’t always lead to faster results.
so there you have it, i hope this cleared some things up and the tips i gave are actionable. good luck!
:)
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Miles holds a masters degree in exercise and nutrition science from the university of tampa and is a certified strength and conditioning specialist. Miles works as a personal trainer based in greenpoint brooklyn where he runs his own studio and focuses on 1-1 training designed to improve movement mechanics to help his clients move well without pain, improve performance and body composition. his mission is to help people live healthier, happier lives through movement.
*There’s 3 stages that occurs in cellular metabolism; first you eat food and digest it to smaller pieces and then those pieces get broken down into even smaller molecules (you eat a steak, that steak gets broken down into protein molecules, those protein molecules get broken down into oligopeptides and free amino acids), second those small molecules get oxidized (electron or hydrogen atoms get removed), third those oxidized molecules turn into water, carbon dioxide, acetyl coenzyme A, oxaloacetate, and alpha–oxoglutarate; acetyl coenzyme A and oxaloacetate move to the krebs cycle where protons get liberated, citrate is formed and your mitochondria has what it needs to synthesize ATp (what your body uses for energy).
