Metabolism is one of those buzzwords with a vague definition that fitness influencers and zealots have capitalized on to push their supplements and products. But what does it actually mean?
The purpose of this article is to help you understand what your metabolism actually is, how it works, and what you can do to maximize each component to ultimately get the most out of your body.
What is metabolism?
Simply put, metabolism is the process by which your body converts what you eat and drink to energy. Your body’s metabolic rate is also known as Total Daily Energy Expenditure (TDEE). This is the amount of calories your body utilizes on a daily basis. This is important to know because it is going to help dictate how much we consume relative to what your goals are.
TDEE is can be divided into several components: Thermic effect of food, Physical activity, and Basal Metabolic Rate.
Thermic Effect of Food (TEF) 10%
The thermic effect of food is the amount of energy it takes for your body to digest, absorb, and metabolize the food you eat. Think of it as “the calories you burn by eating calories.” TEF represents about 10% of your daily calorie output and is largely impacted by the composition of your diet.
If you want to maximize this component of your metabolic rate, there are three things you can do:
1. Eat more frequently
I’m sure you’ve been told, “you need to eat six small meals a day.” Six is not magic. However, the logic behind this recommendation is that the more frequently you eat, the more energy your body burns by digesting the food, thus increasing your TEF.
2. Eat more Protein
Each of the three macronutrients (carbs, fats, and protein) has a specific thermic effect. Protein is the highest, meaning your body needs to use more energy to break down and metabolize it. This is why a high-protein diet has a metabolic advantage over normal or low-protein diets with the same amount of total calories and has been proven to keep you fuller for longer.
3. Eat more Whole Foods
Whole foods are single-ingredient foods that have not been processed, like chicken, steak, fruits, veggies, rice, etc. The more processed a food is, the less effort your body has to put in to digest it. Whole foods have almost double the thermic effect than processed foods.
Physical Activity 20%
The next component, equating to 20% of your metabolic rate, is physical activity. Physical activity is further broken down into two subcategories: Exercise Activity and Non-Exercise Activity.
Exercise Activity Thermogenesis (EAT)
This is the calories burned through intentional, dedicated exerciseー going to the gym, taking a class, going for a run. EAT also includes the calories we burn after the exercise session is finished – this is known as the excess post-exercise oxygen consumption (EPOC). Lifting weights has about a 39 hour EPOC effect, meaning you’re still burning calories for 39 hours post-training. Low intensity cardioー things like a steady pace on the elliptical, treadmill, or bike only have a 4 hour EPOC effect. This is why including weight training in your regiment is critical in order to maximize this piece of the equation.
However, EAT only represents about 5% of this 20% piece. The majority of the calories burned through activity come from Non-Exercise Activity Thermogenesis, or NEAT.
Non-Exercise Activity Thermogenesis (NEAT)
As the name implies, NEAT is the calories burned outside of dedicated exercise time. Every activity you do contributes to your NEAT. Brushing your teeth, making the bed, typing on the computer, waiting in line for your morning coffee… These things all burn calories, and quite a substantial amount!
Simply just moving your body more throughout the day can have a large impact on the calories you burn every day. Simple ways to do this is by taking the stairs instead of the elevator, parking further away, and taking an extra lap around the neighborhood when walking the dog.
To recap, only 10% of your metabolic rate comes from the thermic effect of food and 20% from your activity, equating to 30% of your TDEE, meaning there is 70% left. I’m not a mathematician, but I would say that 70 is much greater than 30. So, why is it that most programs only emphasize the 30%? They focus so heavily on following specific exercises and eating from a specific list of foods while turning a blind eye to the greater contributor to your metabolic rate, your BMR.
Basal Metabolic Rate (BMR) 70%
This is what “keeps the lights on.” Your BMR is the number of calories you burn at complete rest.. No exercise, no moving around, just resting. Meaning if you lie in bed all day, your body will still burn a certain amount of calories to carry out all its many processes to keep you alive, such as breathing, repairing cells, and circulation.
BMR is calculated by several factors such as genetics, gender, hormones, age, and body composition.
Several components contributing to your BMR are not in your control. You can’t change your genetics, your age, or gender. However, something that is in your control is your body composition.
Muscle is one of the most metabolically active tissues in the body. It is an incredibly “expensive” tissue, meaning it burns more calories in the resting state than body fat. Therefore, the more muscle in your body, the higher your metabolic rate.
It is important to note that the inverse is also true. Losing muscle mass will decrease your metabolic rate. Unfortunately, this is where many people wind up in their weight loss pursuits, focusing heavily on cardio-based exercises and dieting. This approach deprives the body of the resources and stimulus needed to maintain muscle mass. When this happens, your body gets really good at offloading muscle tissue and storing body fat, thus decreasing your metabolic rate… The exact opposite of what you want.
That being said, in order to maximize this 70% of your metabolism, it is essential to focus on increasing your muscle mass via strength training.
Understand that you are not doomed by a slow metabolism and your metabolism certainly is not broken. If it were, you’d be dead! It is likely that you are just not maximizing each piece of the metabolic puzzle. I encourage you to audit each piece of the pie to identify where there is an opportunity for change.
To maximize your Thermic Effect of Food… Increase your meal frequency, eat a sufficient amount of protein, and consume mostly whole foods.
To maximize your Physical Activity… Strength train and move your body more throughout the day
To maximize your Basal Metabolic Rate… Focus on improving your body composition by building muscle and decreasing your body fat percentage.
It is my hope that with a foundational understanding of your metabolism and its components, you will be able to start achieving your health and fitness goals and sustaining those results for a lifetime to come.