Calculating your Total Daily Energy Expenditure (TDEE) involves determining how many calories you burn in a day, considering your basal metabolic rate (BMR) and your level of physical activity. TDEE is a useful metric for anyone looking to gain, lose, or maintain weight, as it provides a guideline for how many calories to consume. Here’s how you can calculate it:

Step 1: Calculate Your Basal Metabolic Rate (BMR)

BMR is the number of calories your body needs to perform basic life-sustaining functions such as breathing, circulation, cell production, and nutrient processing—all while at rest. Several formulas can be used to estimate BMR:

• Harris-Benedict Equation (more traditional):

  • Men: BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) - (5.677 × age in years)
  • Women: BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) - (4.330 × age in years)

• Mifflin-St Jeor Equation (considered more accurate by many health professionals):

  • Men: BMR = 10 × weight (kg) + 6.25 × height (cm) - 5 × age (years) + 5
  • Women: BMR = 10 × weight (kg) + 6.25 × height (cm) - 5 × age (years) - 161

Step 2: Adjust for Physical Activity

Once you have your BMR, you need to adjust it based on your level of physical activity to find your TDEE. This is done by multiplying your BMR by the appropriate physical activity level (PAL):

• 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 a week): BMR × 1.725
• Super active (very hard exercise/physical job & exercise 2x/day): BMR × 1.9

Example Calculation

Let’s calculate the TDEE for a 30-year-old woman who is 165 cm tall, weighs 65 kg, and exercises moderately (3-5 days per week):

1. Calculate BMR using the Mifflin-St Jeor Equation:
   $$BMR=10\times 65+6.25\times 165-5\times 30-161=650+1031.25-150-161=1370.25\text{ kcal/day}$$
2. Adjust BMR for moderate activity:
   $$TDEE=BMR\times 1.55=1370.25\times 1.55=2123.89\text{ kcal/day}$$

This value is the estimated total number of calories she would need to consume per day to maintain her current weight, given her level of activity.

Considerations

It's important to note that these calculations provide estimates. Individual energy needs can vary based on other factors such as metabolism, muscle mass, and overall health. For personalized advice, especially if you have specific health conditions or nutritional concerns, consulting with a healthcare provider or a dietitian is recommended.