How to (Actually) Speed Up Your Metabolism

How to (Actually) Speed Up Your Metabolism

By Stephen Brenna, Pn1, Pn2, PPSC

How to (Actually) Speed Up Your Metabolism

Sort of like "the economy", many people view "my metabolism" as some mysterious, unseen force whose fluctuations are beyond our control. Whether it's "slow" or "fast" is simply a matter of age, sex, hormone status, or dumb luck, and we're mostly helpless to do anything about it.

Unless that is, we drink this special tea our skinny girlfriend is selling (that's also a great passive income opportunity?!). Or we head down to the supplement shop and grab the latest fat burner that's going to wake up that lazy metabolism of ours and get it firing on all cylinders.

Both of these options might get something firing, from your backside that is. But believe it or not, loose bowel movements aren't a sign you're burning more calories or losing any body fat.


In the real world nutrition coaching space, it's common to meet with individuals struggling to lose weight, even when they're eating relatively little. Some may argue that dietary recall is poor (and they would be correct) or that calorie counting must be inaccurate if someone is not losing weight in a caloric deficit. While both arguments could be true, some individuals really are eating in what *should* be a caloric deficit for them based on their body type and activity levels, and they still can't lose weight.

So, what gives then? Often, the next turn in the conversation goes something like this: 

"Well, I am getting older. I used to be able to eat whatever I wanted and would never gain weight! My metabolism has just slowed down I guess. I'm just going to have to add more cardio or something…"

In the simplest terms, there is something to the slow metabolism explanation. It's possible that your body isn't processing the same foods in the same way it did when you were younger, but this isn't just an inevitable side effect of aging. Rather, it is a function of your current state of metabolic health, which could be better at age 40 than it was at 25 depending on diet and lifestyle factors. More specifically, the diet and lifestyle factors that affect body composition.


The broad definition of human metabolism is the chemical process by which the food we eat gets converted into the energy we need to function. When it comes to weight loss however, metabolism is often vaguely referenced in regard to caloric expenditure, aka burning calories. The common thought process is, if your metabolism is "slow", you somehow won't burn as many calories as someone else doing the same amount of physical activity. Or that food and body fat sticks to you (i.e. thanks to your sluggish metabolism you don’t burn calories fast enough, ooor something like that).

The reality is, yes, some individuals will expend more calories than others while performing the same types of exercise. Those same individuals will likely also burn more calories while doing absolutely nothing! But the reason why is not the result of a heaven-sent gift of a "fast metabolism". The primary reason some people have a higher rate of caloric expenditure than others is because they have more muscle mass.

Basal metabolic rate (BMR) is defined as the amount of energy an individual uses when lying still and awake. Measured in calories, it represents the minimum amount of energy needed to maintain the basic functions of the brain, heart, lungs, and circulatory system. In layman's terms, BMR is the minimum amount of calories required to keep the lights on in your body.

BMR varies based on age, sex, height, and body weight, but it's estimated that up to 80% of the variability in BMR among adults is the result of how much lean vs. fat tissue one has. As a result, two individuals may be the same age, sex, height AND approximate body weight, but have two different basal metabolic rates due to a difference in body fat percentage. NOT due to one being blessed with a roadrunner metabolism (meep, meep).  

Why is this a big deal? Our basal metabolic rate is something we can intentionally alter via diet and exercise that changes our body composition.


Resistance train and build some muscle! Unless you're planning on getting taller or younger, increasing your body's lean tissue percentage is the number one way to increase your BMR. When you increase BMR, you burn more calories at rest, making it easier to achieve and maintain the caloric deficit necessary to lose weight and shed body fat.

There is one other critical caveat to keep in mind. In order to build muscle mass effectively, one must be consuming adequate calories and appropriate macro and micronutrients. Namely, the right amount of calories necessary to fuel consistent training, as well as appropriate protein intake to facilitate muscle growth and repair. Not to mention a variety of whole fruits and vegetables that provide the vitamins and minerals needed to keep the whole show running smoothly. 

Meaning, if you're trying to build muscle from the basement of your 1000 calorie crash diet, your chances of success are slim. Many people looking to speed up their metabolism should begin by eating more, not less.

This process often seems counterintuitive to those looking to lose weight, especially those stuck in the flawed mindset that increasing muscle mass means getting “bulky”. In reality, building lean tissue almost always results in a net loss of inches in the waistline and other desirable areas. Perhaps most importantly, the more we shift our body composition in favor of lean tissue over fat mass, the more leverage we have in maintaining weight loss without the need for significant caloric restriction. 

Those glory days when you could eat whatever you wanted and not gain body fat? There’s a high likelihood your lean mass percentage was greater then than it is now if you’re struggling with weight loss.

So please, enough with the green tea supplement that might boost your caloric burn by a fraction of a percent. If you want to speed up your metabolism, stop regularly skipping meals and lift some weights.