I’m willing to bet you’ve seen thousands of products claiming to ‘speed up’ metabolism or switch on ‘fat burning cells.’ It’s no wonder why. Many of us feel hopeless to change anything about our weight. It doesn’t help that we’ve been told we have a ‘slow’ metabolism.
But the truth is you can’t really ‘speed up’ your metabolism — at least, not in the context most products would have you believe. You don’t need pills or luck to fix your metabolism. And you’re certainly not ‘doomed’ to fail due to genetics, gender, or your work schedule.
You just need to understand what makes your metabolism tick.
A closer look at metabolism
We all know one person who can eat ‘anything they want’ and still seem to maintain their weight. Meanwhile, it feels like just one or two cheat days can add an extra five pounds to your waistline.
This is what’s known as metabolic adaptation: where your body adjusts to meet your energy needs. Remember, your body is designed to use energy effectively. If you’re receiving more energy than you can feasibly spend, your body will have to store it as fat.
The amount of energy you need each day depends on specific lifestyle factors. This includes energy required for:
- Exercise (~0% to 30% of total energy)
- Incidental movement (~0% to 30% of total energy)
- Digesting food (~8% to 15% of total energy)
- Keeping your body running (~60% to 70% of total energy)
As you can see, the largest portion of required energy goes into maintaining your size and powering your organs and cells. This energy is required even while you sleep — another reason why you can’t exercise your way to weight loss.
Every body requires a certain amount of energy depending on its state and type. Think of the difference between a mouse and an elephant: one requires significantly more energy due to its relative size. And when you think about the difference between an active elephant and a sedentary one, you can see why some people require (and effectively allocate) more energy than others.
The larger you are, the more energy you need to remain at that size. That’s why obese people require 20% more daily energy than lean people, regardless of exercise levels. But not all parts of your body require the same amount of energy as others. Fat requires far less energy to maintain than muscle, which requires an enormous amount of energy (more on this later).
Addressing the misconceptions
There’s been so much noise surrounding metabolic speed that it’s difficult to parse the facts from fiction.
I wanted to address a few of these below so you have a better idea of how metabolism actually works.
Myth: Don’t I need to eat every three hours to speed up my metabolism?
This idea was popularized by some particularly bad science. No, small or more frequent meals won’t ‘speed up’ your metabolism. Quite the opposite — studies show smaller, more frequent meals actually increase hunger and food cravings compared to people who eat three meals per day or less.
Myth: Won’t intermittent fasting make my metabolism worse?
Your body doesn’t constantly need food to keep it alive. Plus, eating less frequently allows your body to regulate hunger hormones like leptin and ghrelin, reduce insulin resistance, and reset cravings.
And no, you won’t enter ‘starvation mode.’ This is only truly a problem for people who are malnourished or unable to eat enough food or nutrients during the feeding windows.
But it is true that fasting incorrectly can lead to muscle wasting and therefore lower energy needs. It’s a good idea to read up on intermittent fasting or work with a metabolic health coach before implementing a routine.
Myth: Isn’t my metabolism low because I’m getting older?
Yes and no — although the numbers are very small. Studies show that metabolic rates remain the same between ages 20 and 60 regardless of gender. After age 60, metabolic rates drop less than 1% per year. This is easily offset by higher muscle mass.
The short version is, age is a very small contributor to your daily energy expenditure. A much greater indicator is muscle mass and activity, both of which you can maintain well past your 60s.
Other uncontrollable factors, including genetics, biological sex, and ethnicity, may also play a role. But research shows they have a very small impact compared to daily lifestyle choices around sleep, nutrition, and exercise (which we’ll get into below).
What actually affects the human metabolism
There are four factors in particular:
Sleep
Poor sleep can reduce your daily energy needs and decrease fat loss by up to 55%. This is likely due to an increase in the stress hormone (cortisol), which makes it harder to lose fat and easier to lose muscle.
Getting enough sleep depends on your body’s unique needs. However, most people thrive between seven and nine hours per night.
This will ultimately help reduce unhealthy food cravings and combat insulin resistance, which is one of the biggest underlying factors of poor metabolic health.
Nutrition
Your focus shouldn’t be on ‘calories in, calories out.’ Instead, focus on eating satiating foods that keep you fuller longer and feed your gut microbiota.
This means a diet in rich whole, real foods like:
- Animal protein
- Seafood
- Eggs
- Vegetables
- Milk
Stay away from processed foods and anything else that contains added sugar, seed oil, and unhealthy preservatives. These damage metabolic health, encourage you to overeat, and alter body composition on a cellular level.
And remember: the healthier your cells are, the more energy you’ll need to power them. Reclaiming metabolic health and reversing mitochondrial damage will increase your capacity to convert food into energy.
Physical activity
Your doctor has likely already told you to exercise more. But you won’t do enough exercise to burn enough calories for meaningful change. Exercise is less about using up energy to get thin and more about strengthening metabolic pathways (including bones and muscles).
Daily exercise will:
- Increase passive energy needs over time
- Stave away sarcopenia and osteoporosis
- Protect against metabolic dysfunction
Any kind of movement counts as physical activity, including walking the dog or biking to work. But not all physical activity is equally impactful for metabolism.
Which leads to my next point:
Muscle mass
Muscle requires more energy than fat to maintain. This means the more muscle you have, the more energy you’ll need to remain at that size.
This isn’t necessarily tied to overall body weight. Thin people with lower BMIs may have a higher muscle-to-fat ratio and be more physically active than visibly muscular people, for example.
That said, please know that you don’t need to be visibly muscular or spend hours in the gym to build healthy muscle mass. Studies show even 11 minutes of resistance training per day can result in long-term increased energy needs.
I wrote a guide on how to exercise for metabolic health if you’re curious about getting started.
How to reclaim a healthy metabolism
Human metabolism isn’t ‘fast’ or ‘slow.’ It simply adapts to fit in with its surroundings.
And if you want to use energy to its best possible efficiency, you’ll need to start by reclaiming your metabolic health.
Here are some resources to help you do just that:
- 5 ways to improve your metabolic health (besides diet and exercise)
- What people with the longest healthspans have in common
- How to improve your metabolic health in 12 weeks or less
