How to Calculate Katch Mc Ardle
What is Katch Mc Ardle?
Katch-McArdle formula estimates basal metabolic rate using lean body mass. It's more accurate in muscular or obese individuals.
Formula
First calculate lean body mass (LBM = weight × (100 - %bodyfat) / 100)
- LBM
- weight × (100 - %bodyfat) / 100) — weight × (100 - %bodyfat) / 100)
Step-by-Step Guide
- 1First calculate lean body mass (LBM = weight × (100 - %bodyfat) / 100)
- 2Then: BMR = 370 + (21.6 × LBM in kg)
- 3More accurate than weight-only formulas
Worked Examples
Input
80 kg, 20% body fat
Result
LBM = 64 kg, BMR = 1755 kcal/day
Accounts for body composition
Common Mistakes to Avoid
- ✕Using inaccurate body fat estimates
- ✕Forgetting that BMR increases with muscle mass
Frequently Asked Questions
When is Katch-McArdle better than Harris-Benedict?
In individuals with unusual body composition: very lean athletes or obese patients.
How accurate is body fat estimation?
Accuracy varies 3-5%; bioimpedance, DEXA, or calipers best. Visual estimation inaccurate.
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