How to Boost Your Metabolism to Lose Fat | 12 Studies Analyzed
Is your slow metabolism preventing you from getting lean?
It’s true. Some people are calorie-burning machines. They can stuff their faces with food and barely (if ever) gain weight.
But it’s not all about being genetically blessed. You too can train your body to achieve a more efficient metabolism. All you need is a basic understanding of human biology.
What's Really Preventing You From Getting Lean?
The body evolved complex processes to regulate its metabolism and keep it constant. Otherwise, your arm may suddenly go limp or your heart stops beating. Just because the body failed to meet their energy requirements one day.
But first, what is metabolism?
- metabolism – a complex bodily process of converting food and drinks into usable energy
However, that’s not what people usually have in mind. When we discuss metabolism we’re actually referring to the individual’s basal metabolic rate [1].
- basal metabolic rate (BMR) – the amount of daily energy (calories) burned while at rest.
To keep you alive your body constantly burns calories. Your phone works the same way. Even if you don’t touch it for a day it will keep using energy to stay on.
How Can You Exploit the Differences in Human Metabolism?
People with high BMR have high energy requirements. They naturally need more energy to function properly. That’s why they can enjoy more food without gaining weight.
However, there’s only about 10% difference between individuals [2]. Even if we examine people at the extreme ends of the spectrum the difference is small.
Let’s consider 2 examples of high and low metabolic rate: 1,800 kcal vs 1,300 kcal.
That’s a 500 kcal difference. A nice dinner at a restaurant can be 1,500+ calories. Having 500 kcal extra is nice. But the whole meal is still not “free”.
If you have a fast metabolism you can enjoy an extra chocolate bar a day. Anything more and you’ll gain weight as easily as everyone else.
It may not sound like a huge advantage but it’s still something, right? So let’s see if it’s possible to improve your BMR.
What Determines Your Unique Metabolic Rate?
The difference between people gets even smaller when you consider the main BMR factors:
- Body size and weight – larger individuals require more calories to maintain their body weight. Similar to comparing the fuel expenditure of a big truck vs a small car.
- Sex and body composition – the higher your body fat percentage the slower your metabolism is.
- Women have more fat than men at the same weight (mostly because breasts contain a lot of fat). Overweight individuals have a poor fat to muscle ratio.
- Age – mostly related to muscle loss and fat accumulation as we get older. The result is that basal metabolic rate goes down over time.
Large lean men in their 20’s tend to have high BMR. Overweight elderly females are usually on the other side of the spectrum. However, regardless of sex and age, high body fat percentage results in universally low BMR [3].
Bottom line: people with similar weight, body composition, sex, and age have almost identical metabolisms.
How to Change Your Metabolism to Speed up Fat Loss
First off, you shouldn't worry too much about slow metabolism.
- Your metabolism has little impact on your weight
- There’s not much you can do to change it
- Other lifestyle factors have a much greater impact
Studies show that BMR differences don’t affect the rate of weight loss when dieting [4].
Notable weight gain is almost never the result of a slow metabolism. But certain medical conditions (e.g. Cushing's syndrome or hypothyroidism) can have that effect.
Those are one of the few examples when metabolic rate can drop significantly. That, of course, leads to a lot of complications and health hazards.
The only meaningful way you can change your metabolism is by improving your body composition. This means building muscle at the expense of fat [5]. But even that will raise your BMR by a couple of hundred calories. Still not impressive.
You should have already realized your metabolism has little impact on your weight. It’s a constant in the energy equation. However, there are a few variables you do have control over.
What Is the True Cure for a “Slow Metabolism”?
Your total energy expenditure is the sum of a few components. If you increase your daily expenditure you burn more calories. This means a faster rate of fat loss. Alternatively, it gives you the option to enjoy more food without gaining weight.
Total daily energy expenditure can be broken down to:
- BMR (basal metabolic rate)
- NEAT (non-exercise activity thermogenesis)
- EAT (exercise activity thermogenesis)
- TEF (thermic effect of food)
As you see, metabolism plays a huge role in energy expenditure. Unfortunately, it’s one of the components you can’t change much [6]. But what about the rest?
NEAT: The REAL Reason Why You Can’t Lose Weight
Non-exercise activity thermogenesis is an umbrella term for all unconscious or unplanned activities and movements. It includes things like:
- walking
- talking
- gesticulating
- nervous tics
- fidgeting
- playing with your hair
- blinking
- etc.
After BMR, NEAT is the second-most-important variable in the energy equation. This is because you’re constantly engaged in some kind of activity. The energy burned during each movement is insignificant (e.g. blinking). But the sum of all is huge [7] [8].
What Makes You a Hardgainer or an Easygainer?
Most components of NEAT are unconscious activities. Your NEAT levels are to a large extent genetically predetermined. Some people are genetically inclined to lead a very active lifestyle. Other just can’t stay still for more than a minute.
That’s the reason why some are labeled as “hardgainers”. When you overfeed such people their metabolism doesn’t change much. But their bodies respond by ramping up their unconscious activity [9]. They become restless and burn off most of the excess energy. Or they (unconsciously) start engaging in more activities.
People who struggle to lose weight lack that adaptation. When they overeat, NEAT levels don’t change. Hence they can’t burn the excess energy from food and it’s stored as fat.
Can You Change That?
Most unconscious movements you can’t control. But you can design your lifestyle in a way that makes you more active.
Here a few examples:
- engage in 20-60 min walks a couple of times during the day
- stand instead of sitting when possible (e.g. standing desk)
- explore activities such as dancing, hiking, or roller-skating
- use a bike instead of a car whenever convenient
- implement a morning activity routine (e.g. 20 mins of yoga or 20 push-ups)
- always take the stairs
It may not seem like a lot. But adding 30-60 mins of walking a day can have you drop 2-3 pounds in a month [10]. And this requires literally no effort on your side.
Stack a few of those extra activities a day and you can expect a notable difference in your weight. Maintaining a lean body also becomes effortless.
Exercise: Michael Phelps' Secret to Eating 12,000 kcal Without Fat Gain
Exercise offers 2 unique advantages compared to the rest of the items on this list
- Exercise energy expenditure isn’t severely restricted by your genetics or circumstances
- The upper limit of calories burned a day is very high
Professional athletes are known to have high energy demands because of their rigorous training. Low BMR or NEAT don’t really affect calories burned during exercise. The more and harder you train the more energy requirements will go up.
Note that a typical workout doesn’t burn more than 300-400 kcals. So unless you’re doing hard training 8+ hrs a day don’t expect any miracles.
The biggest benefit is the total control you have over this aspect of your life. The exercise component of the energy equation can range from zero to several hundred calories. Even more, if we consider the long-term BMR benefits of building muscle.
You can explore different sports, weight training, or cardio. It can be a fun and engaging activity that helps keep you in shape. This is by far your best tool to deal with “bad” weight loss genetics.
For more exercise tips check out “I Never Exercise, How Do I Start?”
Thermic Effect of Food: How a Simple Fix Can Bring Overnight Results
ТEF is the cost of food processing. You see, there’s no free energy. To extract any energy (calories) from the food you have to spend some energy in the first place.
The thermic effect of food is based on the level of processing required. Some foods are more challenging than others. The harder the body has to work, the higher the thermic effect of food. This also increases your energy expenditure.
Commercially processed foods ease the consumption and absorption of nutrients. That improves taste due to rapid taste bud stimulation. But also reduces the food’s thermic effect. Whole foods have the opposite effect.
Which Foods Help Fat Loss?
It’s easy to see how a diet based on processed foods reduces TEF. This makes it hard to lose weight. By improving your diet you can increase your energy expenditure overnight [11]
Here are examples of high-TE foods:
- leafy veggies
- root vegetables
- fruits and berries
- legumes (beans, lentils, etc)
- peas (e.g. green peas)
- low-fat dairy
- lean meats
- Mushrooms
For more nutrition tips check out: The Perfect Grocery List for Ripped Abs
The biggest benefit of eating high-TE foods is they reduce the risk of over-consumption. Whole foods are far more satiating and way less caloric. This makes them ideal for managing hunger and cravings.
Note that TEF impacts your weight loss rate less than exercise. But whole foods are more nutritious and healthy. And this is another reason why you should pay attention to your diet.
Writer’s Note:
Exposing yourself to extreme cold or heat can also increase your energy expenditure This will force your body to react and spend more energy to maintain balance. But the benefits you get are very small. The risk of health hazards is significant if your approach is flawed.
What Is the Most Effective Way to Get Lean?
Let’s sum up everything we’ve discussed so far. If you want to increase your energy expenditure you have to:
- move more (exercise + daily activities)
- pay attention to the quality of the foods you eat
- improve your body composition (add muscle)
But there’s another way to burn fat. Instead of increasing expenditure you can reduce consumption.
It takes 20 seconds to eat a slice of pizza. But you need 20-30 mins of exercise to burn those calories [12]. Managing your weight through daily activity may not be enough to keep up with consumption.
This is why food intake should be your top priority. If you have a lot of weight to lose activity alone won’t get the job done.
Master your eating habits and use movement to supplement your dieting efforts. This will result in the absolute best rate of fat loss.
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References
[1] The functional significance of individual variation in basal metabolic rate
[3] Examining Variations of Resting Metabolic Rate of Adults: A Public Health Perspective
[4] Does basal metabolic rate predict weight gain?
[5] Evidence for Resistance Training as a Treatment Therapy in Obesity
[6] Weekly changes in basal metabolic rate with eight weeks of overfeeding.
[7] Spontaneous physical activity: relationship between fidgeting and body weight control.
[8] Energy expenditure of nonexercise activity
[9] Resistance to weight gain during overfeeding: a NEAT explanation
[10] The Role of Non-exercise Activity Thermogenesis in Human Obesity
[11] Thermic effect of food, exercise, and total energy expenditure in active females
[12] Calories burned in 30 minutes for people of three different weights