What Is Energy Balance (And Why Does It Matter)?
Reviewed By Danielle Glesne, RDN, LD, CDCESWhen we hear the term “calorie” we often think of food. And while food is a delivery system for calories, a calorie is simply a unit of energy.
When we consume calories, we are consuming energy. When our body expends (aka burns) calories, it is expending energy.
And so energy balance is the balance of calories consumed compared to calories expended.
According to the law of conservation of energy, energy cannot be created or destroyed. Energy can only be converted from one form of energy to another, and can only be gained, lost, or stored by an organism.
Simply put, at the end of the day, if your body has left over energy, it will store it for use later. The inverse is also true: if at the end of the day your body has less energy than it needs to perform the day’s tasks, it will use stored energy to do so.
That’s why any discussion about body weight—whether going up, going down, or staying the same—must begin with energy balance.
Energy Balance and Body weight
Energy balance is the driving force behind change in body weight—or lack thereof. Remember: the human body cannot create or destroy energy, it can only convert or store it. Unused energy will be stored for potential use later.
Therefore, if you consume more energy than you expend on average over time, your body weight will increase. This is known as a positive energy balance.
If you consume the same amount of energy as you expend on average over time, your body weight will stay the same. This is known as a neutral energy balance.
If you consume less energy than you expend on average over time, your body weight will decrease. This is known as a negative energy balance.
How the Body Expends Energy
The human body expends energy (aka burns calories) in three general ways:
Basal metabolic rate (BMR)
Thermic effect of food (TEF)
Physical activity (NEAT, EAT)
A person’s basal metabolic rate (BMR) is the energy expenditure required to maintain normal body functions and homeostasis.
Thermic effect of food (TEF) is the energy expenditure required to absorb, digest, and metabolize food and drink consumed.
Both non-exercise activity thermogenesis (NEAT) and exercise activity thermogenesis (EAT) are the energy expenditure required to perform physical activity.
Total Daily Energy Expenditure
The sum total of those energy expenditures equal a person’s total daily energy expenditure (TDEE).
And while your TDEE is unique to you and based on several factors, it’s roughly comprised of:
70% BMR
15% NEAT
10% TEF
5% EAT
Energy Balance and TDEE
Stated another way, if you consume more energy than your TDEE on average over time (positive energy balance), your body weight will increase.
If you consume the same amount of energy as your TDEE on average over time (neutral energy balance), your body weight will remain the same.
If you consume less energy than your TDEE on average over time (negative energy balance), your body weight will decrease.
How to Calculate Your TDEE
If you’re curious what your total daily energy expenditure is, you can use this TDEE Calculator to find out.
That calculator uses the Mifflin-St Jeor formula to calculate an estimate of your Basal Metabolic Rate, and then adjusts the numbers to take your activity level into account.
It’s important to note this is just an estimate of your TDEE. The human metabolism is far too complex—not to mention constantly adapting—for any calculation or testing method to be 100% accurate. But using a TDEE estimate is a terrific place to begin building a plan for progress.
Why Energy Balance Matters
As we’ve seen, energy balance is the driving force behind body weight change. If you have body composition goals, energy balance must be accounted for.
For instance:
If you want to lose weight/fat, energy balance must be accounted for.
If you want to gain weight/muscle, energy balance must be accounted for.
If you want to stay the same weight and reduce fat while building muscle, energy balance must be accounted for.
Energy balance is the foundation of any body transformation discussion, because calories are energy.
Questions?
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