Explaining TDEE, BMR and how to work out daily energy requirements

CreedCoaching
Apr 1
5 min read

When people discuss 'weight-loss' or 'maintance' or anything to do with diets and weight they usally think that by just eating a bit more or cutting carbs is the awnser- it isnt. Most people dont actually understand how many calories they need or how to work this out. Understanding how many calories your body needs each day is essential for managing your fitness goals. The foundation of this process lies in understanding TDEE. This stands for your Total Daily Energy Expenditure. This process contains 4 components, BMR, NEAT, EAT and TEF.

Understanding TDEE and Its Components

Total Daily Energy Expenditure (TDEE) is the total number of calories you burn in a day. It consists of four main components:

1. BMR (Basal Metabolic Rate) BMR is the number of calories your body needs to maintain vital functions while at rest. This includes processes like breathing, circulation, and cell production. It represents the minimum energy expenditure required for survival.

2. NEAT (Non-Exercise Activity Thermogenesis) NEAT refers to the calories burned through non-exercise activities, such as walking around the house, fidgeting, or any other daily movements that are not considered structured exercise. This component can vary significantly from person to person based on lifestyle choices.

3. EAT (Exercise Activity Thermogenesis) EAT encompasses the calories burned during structured physical activities or exercise. This includes workouts at the gym, sports, and any other intentional exercise. Your activity level plays a crucial role in determining your EAT.

4. TEF (Thermic Effect of Food) TEF is the energy expended during the digestion, absorption, and metabolism of food. It accounts for roughly 10% of your total caloric intake and varies based on the composition of your diet (e.g., protein has a higher thermic effect than fats or carbohydrates). This is only a small percentage of your total energy expenditure and varies based on the macronutrient composition of your diet.

Calculating TDEE

To calculate your TDEE, you start with your BMR and then add the calories burned from NEAT, EAT, and TEF. Understanding how each component contributes to your overall energy expenditure can help you tailor your diet and exercise regimen to meet your goals.

The first step would be calculating your BMR (Basal Metabolic Rate), which represents the number of calories your body burns at rest to maintain vital functions like breathing, circulation, and cell production- basically the amount of calories your body needs to just exists. From there, you can determine your total daily calorie requirements based on your activity level.

Below explains how to accurately calculate your BMR and daily caloric needs, breaking down the science behind it and offering practical steps you can follow.

What Is Basal Metabolic Rate (BMR)?

Your Basal Metabolic Rate is the number of calories your body needs to perform basic life-sustaining functions while at complete rest. It accounts for the largest portion of your total daily energy expenditure, typically 60-75%. This means even if you were to lie in bed all day without moving, your body would still burn calories to keep your heart beating, lungs breathing, and organs functioning.

Peoples personal BMR varies due to factors such as:

Age
Sex
Weight
Height
Body composition (muscle vs. fat)

Knowing your BMR gives you a baseline for how many calories your body requires before adding any physical activity. I must note you should never be eating only your BMR amount of calories or below as it will effect your wellness, energy levels and health in the long term.

How to Calculate Your BMR

Several formulas exist to estimate BMR, with the most commonly used being the Harris-Benedict Equation and the Mifflin-St Jeor Equation. The Mifflin-St Jeor formula is considered more accurate by many experts.

Mifflin-St Jeor Equation

For men:

BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5

For women:

BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161

Example:

A 30-year-old woman weighing 70 kg and 165 cm tall would calculate her BMR as:

(10 × 70) + (6.25 × 165) − (5 × 30) − 161

= 700 + 1031.25 − 150 − 161

= 1420.25 calories/day

This means her body burns approximately 1420 calories per day at rest.

Harris-Benedict Equation (Revised)

For men:

BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) − (5.677 × age in years)

For women:

BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) − (4.330 × age in years)

This formula tends to give slightly higher estimates but is still widely used.

Understanding Total Daily Energy Expenditure (TDEE)

BMR only accounts for calories burned at rest. To find out how many calories you need each day, you must factor in your activity level. This total is called Total Daily Energy Expenditure (TDEE).

Activity Multipliers

Multiply your BMR by an activity factor that best describes your lifestyle:

Sedentary (little or no exercise): BMR × 1.2
Lightly active (light exercise/sports 1-3 days/week): BMR × 1.375
Moderately active (moderate exercise/sports 3-5 days/week): BMR × 1.55
Very active (hard exercise/sports 6-7 days/week): BMR × 1.725
Extra active (very hard exercise or physical job): BMR × 1.9

Example:

Using the previous example, if the woman is moderately active:

TDEE = 1420.25 × 1.55 = 2201 calories/day

This is the estimated number of calories she needs to maintain her current weight.

Why Accurate Calculation Matters

Many people underestimate or overestimate their calorie needs, which can lead to unintended weight gain or loss. Using an accurate BMR and TDEE calculation helps you:

Set realistic weight loss or gain goals
Plan meals and portion sizes effectively
Understand how activity impacts your calorie needs
Avoid frustration from slow progress or plateaus

Adjusting Calorie Intake for Goals

Once you know your TDEE, you can adjust your calorie intake based on your goals:

Weight loss: Consume fewer calories than your TDEE. A deficit of 500 calories per day typically results in about 1 pound (0.45 kg) of weight loss per week.
Weight gain: Consume more calories than your TDEE. A surplus of 300-500 calories per day supports gradual muscle gain.
Maintenance: Eat roughly the same number of calories as your TDEE.

Remember, drastic calorie cuts or excessive surpluses can harm your metabolism and overall health. Aim for gradual changes and if this is a long term change make sure it is sustainable.

Factors That Affect BMR and Calorie Needs

Several factors can influence your BMR and daily calorie requirements beyond the basic formulas:

Muscle mass: More muscle increases BMR because muscle tissue burns more calories than fat.
Hormones: Thyroid hormones, insulin, and others can raise or lower metabolism.
Genetics: Some people naturally have faster or slower metabolisms.
Health conditions: Illnesses or medications can affect calorie needs.
Environmental temperature: Cold environments may increase calorie burn as your body works to stay warm.

Because of these variables, use BMR and TDEE calculations as estimates, not exact numbers.

Practical Tips to Track and Adjust Your Calorie Needs

Use apps or online calculators: Many tools automate BMR and TDEE calculations and track your food intake.
Monitor your weight and energy: Track changes over weeks to see if your calorie intake matches your goals.
Adjust based on progress: If you’re not losing or gaining weight as expected, tweak your calorie intake by 100-200 calories.
Include strength training: Building muscle can increase your BMR over time.
Stay consistent: Regularly update your calculations as your weight and activity level change.

Summary

Overall, if you are aiming to understand your bodies calorie requirements in more details Working out your TDEE is an important part of the process. By looking at the components of TDEE (BMR, NEAT, EAT and TEF) we can make reasonable adjustments to stay on track and reach our goals.