By Austin Barton, NSCA Certified Personal Trainer, BS Exercise Science, NCCPT Certified Weight Management Specialist
Whether your fitness goal is to improve your body composition, increase athletic performance, or simply feel more energized, there is one crucial aspect thing you that must be considered above all others:
Your calorie intake compared to your calorie output.
When you learn how to calculate your calorie intake and your calorie output, you’ll be able to truly see what you need to do to achieve the body you want. Calculating your calories burned throughout the day may seem simple, but it can be more complex than you realize.
Understanding Your Total Daily Energy Expenditure
Your calorie output is defined as your TDEE, or Total Daily Energy Expenditure. You can find multiple resources like calculators that can estimate how many calories you burn every day, but this isn’t always the most accurate way. Every single person has a different genetic predisposition to how their body utilizes the fuel they put into their bodies.One method of finding your TDEE may not work as effectively for another!
The difficult part in finding your TDEE is determining how active you are outside of your scheduled workouts. How can you know how many calories you burn walking the dog around the block, strolling to the conference room at work, or tussling with the kiddos in the backyard?
The most important question to ask is: “Why do we burn these calories?” When you can answer this question, new pathways that relate to your goals will open up to you.
In the following paragraphs, descriptions of where your calories are being used will be presented. Additionally, you will be able to figure out how to use the scientific method to determine your personal TDEE and cater to your own fitness goals.
When trying to determine how to calculate your TDEE, there are three primary components to your daily calorie expenditure:
- Basal Metabolic Rate (BMR)
- Calories burned through activity
- The thermic effect of food
Basal Metabolic Rate
To start, let’s look at a quick definition of “metabolism”. We hear the word “metabolism” all of the time, and it is defined as “the chemical processes that occur within a living organism in order to maintain life.”. In other words, your BMR is the minimum number of calories you need to consume in order for your body to work the way it’s intended to. When you consume and digest carbohydrates, fats and proteins, these molecules are then used to generate cellular energy, which will allow your organs to function at their optimal level.
Our bodies were built to have our best interest in mind; everything runs “in the background” to maintain the functions necessary for life. Skeletal muscles around the ribcage contract on their own to expand our chest allowing us to breathe; smooth muscle moves our consumed food through our digestive tract for absorption and cardiac muscle pumps our heart so blood can carry oxygen to areas that need it. That is where your BMR comes in!
The majority of the calories you burn every day are used to simply keep your body alive. You burn calories when you breathe, when your heart beats, and when your smooth muscles move consumed food through your digestive tract. This is what makes up your BMR.
Your BMR can be changed and it is typically changed through exercise. As you increase the amount of muscle mass your frame carries, you increase your BMR. Why? More muscle mass = more metabolic activity! Therefore, resistance training is crucial to improving your fitness level and overall health. The more muscles you have, the more calories your body will burn throughout the day, even when you aren’t doing back squats with a barbell.
In the realm of fat loss, many people make the mistake of not considering their BMR. As you likely know, glucose is the primary source of energy for our bodies. When you eat below your BMR, your body will fight to stay alive by pulling stored fat in adipose tissue and stored glucose in muscle and the liver. The body can only carry approximately 2,000 calories of stored glucose on average, while fat stores an infinite amount of energy. Remember, the body naturally craves glucose. This is why it is imperative that you do not eat below your BMR.
In a nutshell, gluconeogenesis means that the body begins to break down your muscle tissue to create more glucose. At the same time, your BMR will decrease, This process occurs in the liver and kidneys and what occurs is a breakdown of your muscle mass into their smallest units called amino acids. These free amino acids combine with two molecules called glycerol and pyruvate to generate glucose. When we starve our body of the calories it needs to function properly, we lose muscle mass.
This means our BMR decreases. This is the last thing you want when you are trying to be healthier because it means storing fat from overeating becomes more likely!
Now that you understand the importance of BMR, here is how you can calculate it. The quickest, but less accurate way to determine your BMR is to use the Mifflin-St. Jeor formula, Have your height, weight, age and gender at the ready for this equation. Once you find your BMR, you can multiply it by a factor based on your activity to get a rough estimate of your TDEE. These factors range from 1-2 and it is based on how often you exercise per week. They are given to you with descriptions on the above website. If your goal is to lose fat, you must eat fewer calories compared to your TDEE. The opposite is true if you wish to gain weight.
A time consuming, but more precise way you can find your BMR is to visit a testing facility. There, they can use equipment to find out what your personal BMR is. Depending on your level of muscle mass, you may have a higher or lower BMR than what the Mifflin-St. Jeor equation predicts!
Calories Burned Through Activity
The next component of your TDEE is calories burned through activity. This is mainly dependent on locomotion, or how much you move your body throughout the day. As you contract your skeletal muscle, your heart rate increases because there is a higher demand for oxygen at the contracting muscles. When your heart rate increases, there is a higher demand for your metabolism to be active!
There are 168 hours in a week, and if you get 8 hours of sleep every night like you should, you have 112 hours to be active. You may exercise for one hour, five days a week at your local EōS gym, which leaves you with about 107 hours of opportunity to be active outside of the gym. I implore you to make an honest appraisal of what you do during those 107 hours. Are you sitting for the majority of those hours, or are you up on your feet?
What you do with that extra time will go a long way toward determining your TDEE.
This is where things can get tricky. Two people with the exact same height, weight, age, gender, and body fat percentages can have two different TDEEs if their daily lives consist of different levels of activity. Comparing an accountant who sits in front of a computer during the workday versus a construction worker who is constantly moving is a great example.
If you want to track your activity in the most accurate way, purchase a fitness tracker that monitors your heart rate. These trackers can tell you how many calories you’re burning through activity based on how your heart rate changes during the day. If a fitness tracker is out of your budget, there is a way around it. You must first consider your goal. Let’s use fat loss as an example.
First, use the calculator mentioned above to determine your BMR and TDEE. Next, subtract 500 calories from the TDEE and that number will be how many calories you should eat in a day to expect some level of fat loss. Finally, stick to that number of calories per day for a month and re-measure your body fat percentage and total weight loss. If you’re not losing fat, you’re eating too many calories! If you’re losing more than 2 lbs per week, you’re eating too little!
The Thermic Effect of Food
Remember, our bodies work to keep us alive. In the case of digestion, our digestive tract requires energy to digest, absorb and store the food we eat. In general, you can assume that you will burn off 5-10% of the calories you eat from fat and carbohydrates simply through digestion. In other words, if you eat 1,000 calories of fat or carbohydrates, about 50 to 100 calories will be burned through digestion. Overall, protein has the highest thermic effect at approximately 25%. If you have 200 calories of chicken, roughly 50 calories will be used to digest it. Keep in mind that the calories burned or not burned from the thermic effect will not make or break you achieving your goals. However, there are ways to understand why certain foods are more conducive to weight gain or loss.
In simple terms, the thermic effect of food can be slightly increased or decreased based on the kind of food you eat. When it comes to carbohydrates, the complexity of the carbohydrates you eat will have different effects. For example, a 12 oz soda that has 140 calories has a lower thermic effect because the simple sugars within the liquid can be digested very rapidly, thus less energy is required to digest it. If you were to eat 140 calories of sweet potatoes, the long chains of starch within the potato mixed with fiber require far more energy to break down and digest. Therefore, your body must increase its metabolic rate within the digestive system to make sure it is properly digested and absorbed, which means more calories burned!
A diet rich in complex carbohydrates, unsaturated fats, fiber, and protein will be the most thermic diet one can have! Of course, you’ll need to learn how to calculate your calorie intake as part of this process.
I’ve just given you a lot of information to consider, but when you put it into practice, you’ll see how calculating your TDEE can help you better manage your health and fitness goals.
Let’s put this whole process into action with an example. After you read this, do it for yourself!
Meet Carl. Carl is 25 years old, 5’10”, and 215 lbs with 30% body fat. His goal is to burn off fat and get down to 180 lbs. He is also expecting to exercise five times per week. However, he has a very sedentary job and doesn’t get much activity outside of the gym.
Carl’s first step is to determine his BMR. He uses the Mifflin-St. Jeor equation to find that he burns approximately 1,969 calories per day in order to stay alive. If he sticks to his goal of exercising five days per week, he can multiply his BMR by a factor of 1.55 to get a TDEE of 3,051 calories per day. We assume that this is his TDEE because he does not get any activity outside of his scheduled workouts. However, there is a possibility that his TDEE is a few hundred calories more when he’s walking around work or his home. Since his goal is to burn off fat, he needs to eat 500 calories less than 3,051 calories, which is 2,551 calories.
His diet consists of whole grains, plenty of lean protein, fibrous vegetables, and unsaturated fat. Therefore, the thermic effect of the food he eats will burn more calories than if he were eating mostly refined grains, sugar, low protein, and low fiber.
After Carl learns how to calculate his calorie intake, let’s imagine that he sticks to eating 2,551 calories per day for an entire month and he exercises five days per week. He then checks his progress at the end of the month by weighing in and measuring his body fat percentage. His body fat percentage went down by two percent and his weight dropped five lbs pounds over four weeks. At a rate of about.one pound lost per week with a drop in body fat percentage, it becomes clear to him that this is very sustainable over time! If he were to see no changes at all, or even experience an increase in body fat and weight, 2,551 calories is too high! He will then have to re-evaluate how many calories he consumes every day and check again after the next month passes.
In essence, Carl is using the scientific method to determine how many calories his body needs to lose the fat he wants to shed. You can take this method to bring a more scientific and reliable approach to your own weight and body fat loss! The science really isn’t too hard. Just make sure you understand how to calculate your calorie intake.
Check the labels on everything you eat and be sure to look at what a “serving size” consists of. Lots of free and low-cost programs can help you track your daily calorie consumption.
You can also go to your local EōS Fitness to ask about our EōS nutrition program. Each one of our locations also offers personal training services. A personal trainer can devise a personalized exercise plan for you and guide you in your nutrition goals as well. Learn more about our personal training program at EōS Fitness.
Austin Barton is a certified personal trainer and NCCPT certified weight management specialist. He received his bachelor’s degree in exercise science. Follow Austin on Instagram @Austinbartonfitness, on Twitter @Austinbartonfit, and on YouTube at Youtube.com/austinbartonfitness