Understanding your body’s energy needs is important for a healthy lifestyle. Two key numbers we must know about are your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE). Your BMR is the number of calories your body needs to function at rest, while your TDEE includes all the calories you burn in a day through activities and exercise.
One popular way to calculate these numbers is by using the Mifflin-St Jeor Equation. This equation helps you estimate how many calories you need each day based on your age, weight, height, and gender. Knowing your BMR and TDEE can help you make better choices about what to eat and how to exercise.
In this article, we will guide you through the steps to calculate your BMR and TDEE using the Mifflin-St Jeor Equation. By understanding these calculations, you can set realistic goals for weight loss, gain, or maintenance, and create a plan that fits your personal needs.
What is TDEE?
Total Daily Energy Expenditure (TDEE) is the total number of calories your body needs in a day. It encompasses the calories burnt while at rest (BMR) and during various activities like exercise, work, and daily tasks.
Mifflin-St Jeor Equation to calculate BMR and TDEE:
The Mifflin-St Jeor Equation is a straightforward method for calculating TDEE, starting with the determination of Basal Metabolic Rate (BMR):
Step 1: Calculating Basal Metabolic Rate (BMR)
The BMR calculation is a little different for men and women:
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
This step gives you the calories your body requires at rest, without considering any additional physical activity.
NOTE: If you don’t want to do manual calculations, you can use our BMR calculator which will save you time and effort.
Step 2: Activity Level Calculation
To calculate your TDEE, you need to factor in your activity level. Here are the activity factors for different levels:
- Sedentary (little or no exercise): Multiply BMR by 1.2.
- Lightly active (light exercise or sports 1-3 days a week): Multiply BMR by 1.375.
- Moderately active (moderate exercise or sports 3-5 days a week): Multiply BMR by 1.55.
- Very active (hard exercise or sports 6-7 days a week): Multiply BMR by 1.725.
- Extremely active (very hard exercise, physically demanding job, or training twice a day): Multiply BMR by 1.9.
Step 3: TDEE Calculation
Multiply your BMR by the activity factor that corresponds to your lifestyle.
TDEE = BMR × Activity Factor
Example Calculations:
Let’s put this into practice with two examples.
Example 1: Sarah
Sarah is a 25-year-old woman weighing 60 kg, standing at 160 cm. She engages in moderate exercise 3-5 days a week.
BMR = (10×60) + (6.25 × 160) − (5 × 25) − 161
BMR = 1314
Activity Factor: 1.55
TDEE = BMR × Activity Factor
Sarah’s estimated TDEE is approximately,
TDEE = (1314) × (1.55) ≈ 2036.7 calories.
Example 2: James
James is a 30-year-old man weighing 80 kg, standing at 175 cm. He has a very active lifestyle, engaging in hard exercise 6-7 days a week.
BMR = (10×80) + (6.25 × 175) − (5 × 30) + 5
BMR = 1748.75 (we round it to 1749)
Activity Factor: 1.725
TDEE = BMR × Activity Factor
James’s estimated TDEE is approximately,
TDEE = (1749) × (1.725) ≈ 3017 calories.
If doing the math on your own feels like too much work, there’s a simpler way! You can use an online tool called a TDEE calculator. One of the most popular and accurate ones is on tdee-calculator.net. This tool makes it super easy to find out how many calories your body needs every day without having to do any complicated calculations. Just input some basic information, and it does the job for you!
Conclusion:
Calculating your BMR and TDEE using the Mifflin-St Jeor Equation is a simple yet effective way to understand your body’s energy needs. By knowing these numbers, you can make informed decisions about your diet and exercise routines, helping you achieve your health and fitness goals.
Remember, your BMR tells you how many calories your body needs to perform basic functions at rest, while your TDEE includes all the calories you burn throughout the day. Using these personalized numbers, you can create a balanced plan that fits your lifestyle, whether you aim to lose weight, gain muscle, or maintain your current state. Regularly monitoring and adjusting based on your progress will keep you on track toward a healthier, more active life.