1. What equation did you use and why?
2. What was your calculated BMR? Show your work.
3. What activity level number did you use to multiply by your BMR to get your caloric needs? How did you arrive at using this activity level?
4. What was your calculated caloric needs for a typical day? Show work.
5. How could you use the number you got to lose, gain, or maintain your weight? Be specific. Share your goals and how you will achieve them. This question should be at least 1/2 - 1 page.
Determining Individual Calorie Needs
The Harris-Benedict Equation is a formula that uses your BMR and then applies an activity factor to determine your total daily energy expenditure (calories). The BMR formula uses the variables of height, weight, age, and gender to calculate the Basal Metabolic Rate (BMR). This is more accurate than calculating calorie needs based on body weight alone. The only factor it omits is lean body mass and thus the ratio of muscle-to-fat a body has. Remember, leaner bodies need more calories than less lean ones. Therefore, this equation will be very accurate in all but the very muscular (will underestimate calorie needs) and the very fat (will overestimate calorie needs).
Harris-Benedict Equation:
For men, BMR = 66.5 + (13.75 x kg) + (5.003 x cm) - (6.775 x age)
For women, BMR = 655.1 + (9.563 x kg) + (1.850 x cm) - (4.676 x age)
1 inch = 2.54 cm. 1 kilogram = 2.2 lbs.
As recently as 2005, the ADA (American Dietetic Association) published a comparison of various equations. The Mifflin-St Jeor equation was found to be the most accurate, especially with young adults with more muscle mass and obesity:
Mifflin-St Jeor equation:
Men: RMR = (9.99 x weight in kg) + (6.25 x height in cm) - (4.92 x age) + 5
Women: RMR = (9.99 x weight in kg) + (6.25 x height in cm) - (4.92 x age) - 161
Katch-McCardle Formula:
This formula is a variation on the basic Mifflin-St Jeor equation that will base the equation on Fat-Free Mass (FFM) or Lean Mass. This is more accurate for those who are leaner (and who know their body fat percentage!).
Men & Women: BMR = 370 + (21.6 x lean mass in kg)
Where Fat-Free Mass = Weight in kg - (Body Fat Percentage * Weight in kg).
After calculating the BMR, exercise is factored in. Depending on the exercise level chosen, the BMR will be multiplied by anything from 1.2 to 1.9.
1. If you are sedentary (little or no exercise): Calorie Calculation = BMR x 1.2
2. If you are lightly active (light exercise/sports 1-3 days/week): Calorie Calculation = BMR x 1.375
3. If you are moderately active (moderate exercise/sports 3-5 days/week): Calorie Calculation = BMR x 1.55
4. If you are very active (hard exercise/sports 6-7 days a week): Calorie Calculation = BMR x 1.725
5. If you are extra active (very hard exercise/sports & physical job or 2x training): Calorie Calculation = BMR x 1.9
This provides us with maintenance calories. To get the fat loss figure, 20% is subtracted. The extreme fat loss figure has 40% subtracted. However, there is a "rock bottom figure" that equates to 8 calories per pound of body weight - the extreme fat loss that can be gained.