As important physical fitness can be in establishing overall health, I personally view it as a mere supplemental piece to the absolute essential concepts of nutrition. Understanding what role caloric intake plays in the overall scheme of energy expenditure is something that is relatively simple to understand and can truly reap tremendous weight loss benefits for beginners and experts alike. Other more complicated topics such as macronutrients, supplements, and performance related nutrients aren’t as important for beginners, and thus will be discussed in future articles.
For a beginner, it all begins with the concept of Total Energy Expenditure (TEE). Total Energy Expenditure describes the three major bodily processes that utilize the calories we ingest from the foods and beverages we consume. Take a look at the chart below:
As you can clearly see, the three main components of TEE are Basal Metabolic Rate, Physical Activity, and Dietary Thermogenesis (also known as the Thermal Effect of Feeding). By far the biggest component of energy use is the Basal Metabolic Rate (BMR). It uses up a massive 60 to 75 percent of the total energy the human body uses, and I think of it as “Life Energy” because all of these calories are utilized in the maintenance of proper organ function, the regulation of internal body temperatures, and much more. Basal Metabolic Rate does not require a single movement to burn calories. In fact, it is a measurement of how many calories an individual burns over a 24 hour span by just sleeping or sitting. This rate is different for everyone and is affected by age, lean body mass, body size, height, weight, and other physiological processes. There are several BMR calculators online, and a quick google search will allow you to discover a relatively accurate estimate of the number of calories your body burns by simply maintaining itself.
The next biggest component of TEE is physical activity, and this is the only component of total energy expenditure that you have complete control over. Participating in exercise, regardless of its intensity, increases energy demands placed on the body. In order for the body to satisfy the requirements of these demands it uses the energy from calories ingested from food. Think of Total Energy Expenditure as a test and physical activity is thirty percent of that test. If you don’t take it the best you can get is a 70. If you do well, you burn more calories, and thus lose more weight, or can eat more food.
The final component of TEE is dietary thermogenesis. This is a very scientific term to simply describe the energy required to digest food, and thus I think of it as “Digestion Energy”. This is for the most part completely out of your hands, and your body will burn ten percent of total calories ingested autonomously. It is possible to manipulate this number by eating frequent meals, but overall this will not make or break much.
How Weight Loss Works
Now that we know how the energy ingested from food is utilized, we can understand exactly how weight loss works.
Total Calories Ingested (TCI) – Total Energy Expenditure(TEE) = Net Caloric Deficit/Surplus
If (TCI-TEE) is > 0 Weight will be gained (Caloric Surplus)
If (TCI-TEE) is = 0 Weight will be maintained
If (TCI-TEE) is < 0 Weight will be lost (Caloric Deficit)
If you subtract total calories burned in a day (TEE) from the total calories you ingested from food (TCI), you will arrive at a number that represents your net caloric value. If this number is positive you have a caloric surplus, meaning you ingested more calories than you burned and thus will gain weight. If the opposite occurs and you have a negative number, you have a caloric deficit. This means you burned more calories than you ingested, resulting in weight loss. If the number is zero, you will neither gain nor lose weight as you have burned the same amount of calories that you have ingested. To calculate exactly how much weight is gained or lost, you take the surplus/deficit amount of calories and divide it by 3500. For example, if you had a surplus of 700 calories, you would gain 700/3500 (.2) pounds.
Putting it All Together
Now that we understand exactly how weight loss is achieved, I think providing an example of calculating energy balance would be helpful. So let’s observe a sample of my own personal daily caloric receipt to understand this better.
Alex’s Caloric Receipt
Caloric Deficit of 858 calories
As you can see, I ate three total meals throughout the day, and two snacks in between these meals for a total of five meals. The way you figure out the caloric values for each of these meals is to ensure you are tracking the calories that are portioned for the serving size you consume. For example, if I was eating a serving size of chicken (one piece) I would see on the back that this relates to 425 calories. You must do this for every meal you eat or drink, and at the end of the day tally up the total amount of calories you consumed. However, if you are busy, or just lazy like me, you can use one of several phone applications that will not only do all the math for you. All you have to do for these apps is search what you ate, tell them how much you ate, and then it will tell you exactly how many calories you consumed. It will also keep track of your calories for the day. If we add all the calories from my meals together, we get a total of 1800 calories, and this number represents by total calories ingested for the day.
Now that we figured how many calories I ingested, it is time to figure out how exactly I calculated my total energy expenditure. If you do a quick search on Google for “Basal Metabolic Rate Calculator” you will find an abundance of websites that will ask for your height, weight, age, and gender. If you are willing to provide this information, the websites will give you a rough estimate of your Basal Metabolic Rate (BMR). This rate stays relatively constant and only changes with increases in the things mentioned above (age, height, weight, etc.). After plugging this information in, my estimated BMR was 2078 calories. In addition to our BMR, we still have to calculate my Dietary Thermogenesis (Digestion Energy) and my physical activity to see exactly how many calories I burned. Digestion energy is simply about ten percent of the total calories you consumed. So for this, I added the calories consumed from breakfast, lunch, dinner, and snacks (1800) and then multiplied it by (.1) resulting in 180 burned calories. As far as calculating exercise goes, you can either purchase a heart rate monitor and it will measure your burned calories, or you could also use apps made for phones that will provide an estimate of how many calories you burned during your workout based off what you did and how long you did it. Add all three of these things together, and you will get your total energy expenditure.
Although these numbers were artificially created (except for BMR), you can see that I subtracted my ingested calories from my total energy expenditure to find out that I was at a calorie deficit of 858 calories, which would be amazing. If everything were to stay exactly the same (highly unlikely), I would burn a total of 6006 calories in one week, and thus lose approximately 1.71 pounds in that week. I calculated this number by multiplying my daily caloric deficit by seven and then dividing that number by 3500. Generally, most people try to be at a deficit of 500 calories per day, because this means that they will burn exactly one pound a week.
Weight loss, as you can probably see, is a very inexact science for someone who isn’t necessarily an expert in nutrition like most of the population is. It relies heavily on technology measuring ingested calories, tracking how many calories we burn in workouts, and our Basal Metabolic Rate. However, understanding how weight loss work is incredibly important, and learning how to track calories really can make a tremendous difference for people who struggle with their weight. With a little precision and discipline, a new and better life is completely attainable!
Author: Alex Perelló – click here to view his bio and other articles
*As a certified personal trainer, I am to make explicitly clear that I am not a qualified to create individualized dietary plans, and I am not necessarily a nutrition specialist. However, I have taken several college courses on nutrition, received several basic nutritional guidelines while studying for the certification, and have years of experience of personal research. This article reflects some useful information I have discovered through these endeavors.