1. What is the TDEE Calculator for IIFYM?

The TDEE (Total Daily Energy Expenditure) calculator estimates your daily calorie needs using the Mifflin-St Jeor equation, which is considered one of the most accurate formulas for calculating basal metabolic rate (BMR) and TDEE for IIFYM (If It Fits Your Macros) approach.

2. How Does the Calculator Work?

The calculator uses the Mifflin-St Jeor equation:

Where:

• \( weight \) — Body weight in kilograms (kg)
• \( height \) — Height in centimeters (cm)
• \( age \) — Age in years
• \( activity\_factor \) — Multiplier based on activity level (1.2-1.9)

Explanation: The equation calculates your Basal Metabolic Rate (BMR) first, then multiplies it by an activity factor to estimate your total daily energy expenditure.

3. Importance of TDEE Calculation

Details: Knowing your TDEE is essential for effective weight management, whether your goal is weight loss, maintenance, or muscle gain. It forms the foundation of the IIFYM approach to nutrition.

4. Using the Calculator

Tips: Enter your weight in kg, height in cm, age in years, and select your appropriate activity level. All values must be valid (weight > 0, height > 0, age between 1-120, activity factor 1.2-1.9).

5. Frequently Asked Questions (FAQ)

Q1: What is IIFYM?
A: IIFYM (If It Fits Your Macros) is a flexible dieting approach that focuses on meeting daily macronutrient targets rather than restricting specific foods.

Q2: How accurate is the Mifflin-St Jeor equation?
A: It's considered one of the most accurate BMR equations, with about 70-80% accuracy for most populations when activity factors are properly estimated.

Q3: How do I choose the right activity factor?
A: Select based on your typical weekly activity: Sedentary (office job), Lightly Active (light exercise 1-3 days/week), Moderately Active (moderate exercise 3-5 days/week), Very Active (hard exercise 6-7 days/week), Extra Active (very hard exercise and physical job).

Q4: Should I adjust my TDEE over time?
A: Yes, as you lose/gain weight or change activity levels, recalculate your TDEE every 4-6 weeks for optimal results.

Q5: Can this calculator be used for weight loss?
A: Yes, subtract 300-500 calories from your TDEE for weight loss, or add 300-500 calories for weight gain, while maintaining proper macronutrient balance.