The Benefit of Understanding the Caloric Energy Equation

A few years back a family friend approached me and asked if I could help him lose some weight. Like so many, he had fallen prey to the gradual accumulation of excess body fat and was now experiencing some adverse effects to his mobility and a general decline in his quality of life. He wanted some understanding of things he could do to regain a healthy body weight which would allow him the ability to “go-and-do” as he had before.

I was happy to contribute to his efforts. I began by asking him, “Do you know what the Caloric Energy Equation is and why it is important to understand for weight loss”? While I was pretty sure I knew that his response would be “no”, I wanted to start our work together by teaching this important concept. I have learned over the years that when people really come to understand true and correct principles it helps them to better govern their lives, or in this case, make a meaningful change toward healthy weight reduction.

What is the Caloric Energy Equation?

The Caloric Energy Equation is a formula used to determine the total energy or calories (Total Energy Expenditure) a person burns during a day (24-hours), consisting of an individual’s Resting Metabolic Rate, Activity of Daily Living, and Thermal Effect of Food.

• Resting Metabolic Rate (RMR): The number of calories a body burns during a 24-hour period while at rest and fasting (no food or water consumed). This is the energy required to keep your heart beating, your lungs breathing, your liver functioning, your muscles innervated and tone, your glands secreting, and your body temperature regulated.
• Non-Exercise Activity Thermogenesis (NEAT): The number of calories a body burns to support normal daily activity (sometimes known as activities of daily living) that are beyond a resting state. This entails the calories burned to perform your normal daily tasks such as walking, grooming, cooking, cleaning, performing household or workplace chores/tasks, fidgeting, etc. Literally, any activity that is not planned exercise.
• Planned Exercise Caloric Expenditure (PECE): The number of calories burned while engaging in planned exercise. This entails those activities that are planned and built into your day to increase your aerobic fitness and muscular strength. Activities include brisk walking, jogging, cycling, resistance training, athletic events, etc.
• Thermal Effect of Food (TEF): The energy or calories your body must expend to break down, digest, absorb, and assimilate the nutrients in the foods consumed. Yes, the body must burn calories to obtain the calories and nutrients contained in the foods and beverages consumed.
• Total Energy Expenditure (TEE): The total calories your body burns in a 24-hour period – the summation of RMR, ADL, and TEF.

What is Energy Balance?

Energy balance is the comparison between a person’s Total Energy Expenditure or calories burned, and the total number of calories that person consumes during the same 24-hour period (Total Caloric Intake or TCI). If the energy equation is balanced (body weight remains the same), if positive (an increase in body weight will occur), and if negative (a decrease in body weight will occur). Of course, daily fluid shifts in body water content can temporarily affect the equation results but does not impact the caloric content comparison and if these comparisons are consistent over time, the describes weight changes will occur.

The Aw hah Moment

I will never forget the moment when I explained this concept to my friend and he fully and accurately understood it. His response was something like this, “So what you are telling me is weight loss is a simple math equation. If I ensure that the number of calories I eat each day is less than the number of calories I burn each day, I will lose weight. Is that correct? Is it that easy?“

I immediately responded that “Yes, what you have stated about the math equation and weight loss or weight gain is accurate, but that your statement of it being easy is not accurate.” I went on to explain that actors like blood sugar levels affecting appetite, emotional responses to food, differences in food composition of particular foods you might eat can affect the number of calories burned in the Thermal Effect of Feeding, the challenges of meal planning and a busy life schedule, the impact of refined sugar intake on insulin and other hormones, can and do influence a person’s body weight loss efforts. However, I did reiterate that if in the end he burned more calories are than he consumed, he would indeed lose weight. The laws of thermogenesis govern the energy balance and cannot be altered.

My friend found this fascinating, and he was sure he could do the work and work the math to lose his excess weight and return to the body and quality of life for which he was seeking. He then asked me to give a relatively simple answer to the question he was about to pose. His question was this, “in a nutshell, what do I need to do to swing the caloric energy equation in my favor, so I can lose my excess weight?“

The Simple Answer

Trying to be true to his request for a simple answer I responded, “You need to do the following and find fun and excitement in doing it:

• Daily, create a modest restriction between the calories consumed and the calories burned and do it on a consistent basis.
• Work to significantly eliminate refined sugars from your diet while increasing good sources of lean protein
• Engage in moderate physical activity each day – both aerobic exercise and resistance training
• Increase the calories your burn in your activities of daily living by simply moving more and looking for ways to incorporate movement into everything you do
• Experiment with and make modifications to lifestyle strategies that will help you deal with appetite swings, emotional responses to food, and other barriers to successful behavioral modification

Estimate Your Caloric Energy Equation

Because the focus of this article is the caloric energy equation, let’s walk through the steps to estimate the total number of calories you burn in a day, your total energy expenditure.

Step 1: Estimate your Resting Metabolic Rate (RMR).

• Men: (10 x Wt in kg) + (6.25 x Ht in cm) – (5 x age in years) + 5 = RMR
• Women: (10 x Wt in kg) + (6.25 x Ht in cm) – (5 x age in years) – 161 = RMR

   

Step 2: Estimate your Activities of Daily Living (ADL).

NOTE: For simplification, I am combining Non-Exercise Activity Thermogenesis (NEAT) and Planned Exercise Caloric Expenditure (PECE) together under Activities of Daily Living (ADL).

• RMR x Activity Level Factor
  

  Sedentary Activity Level Factor (1.05): person only does typical daily activities like reading, TV watching, and nothing more.

  Low Activity Level Factor (1.25): person engages in <30 minutes per day of moderate to vigorous activity in addition to normal daily routine.

  Active Level Factor (1.4): person engages in 30 to 60 minutes per day of moderate to vigorous activity in addition to normal daily routine.

  Very Active Level Factor (1.55): person engages in >60 minutes per day of moderate to vigorous activity in addition to normal daily routine.

   

Step 3: Estimate your Thermal Effect of Food (TEF): There are several factors that affect TEF including age (decreases with age), Insulin Resistance (obesity and type 2 diabetes reduce TEF), but a person’s level of physical activity increases TEF, and the composition of the foods consumed affects TEF with protein producing a higher TEF compared to fat and carbohydrate. Therefore, a rough estimate of TEF is 10% of the combined caloric expenditure of RMR and ADL.

Step 4: Add the three components of the Caloric Energy Equation together.

• RMR + ADL x .1
  TEF = Total Energy Expenditure (TEE)

Example Calculation

A 38-year-old female who is 5’7″ tall, weighs 169 pounds, and engages in less than 30 minutes of moderate to vigorous activity per day.

RMR: 10 x 76.8 = 768, 6.25 x 170.2 = 1063, 5 x 38 = 190, 161

• 768 + 1,063 = 1,831 – 190 = 1,641 – 161 = 1480
  

ADL: 1480 x 1.25 = 1,850 (1850 – 1480 = 370)

TEF: 1,850 x .1 = 185

Total Energy Expenditure (TEE): 1480 (RMR) + 370 (ADL) + 185 (TEF) = 2035

Once you have your estimated total energy expenditure you have an idea of how many calories your body burns each day. Then determine a modest restriction in the calories you will consume each day (around 500 to 750 calories) and strive to keep your caloric intake to that amount. By doing so you create a caloric deficit, and the body is forced to draw energy from its fat stores to fuel the components of the Caloric Energy Equation – and you lose weight.

TEE – (500 to 750 calories) = Your daily target of calories to consume

• 2,035 – 500 = 1,535
  (recommended daily caloric intake)

This example produced a daily negative energy balance of 500 calories. At 7 days per week this would result in a weekly negative energy balance of 3,500 calories (7 x 500 = 3,500), the equivalent of 1 pound of fat lost per week, as one pound of fat equals 3,500 calories.

One Final Word

Keep in mind that successful weight loss requires some trial and error. This can actually be a fun experience and will increase your knowledge of the skills required for success weight loss and weight maintenance. The summation of successfully executing the skills you develop will certainly lead to your reaching your goals when applied consistently over time. Success to you.

Lynn Perkes is a full-time faculty member at Brigham Young University-Idaho teaching courses in Kinesiology and Biomechanics, Applied Kinesiology and Assessment, Therapeutic Exercise, Physical Therapist Assistant classes, and Health Appraisal and Prescription. He writes part time for ProhealthcareProducts.com, which sells healthcare, therapy, fitness, and personal protective equipment products.