What Lean Body Mass Includes
LBM is everything in your body that isn't fat: skeletal muscle, smooth muscle, cardiac muscle, bone, water, organs, connective tissue. The largest component is skeletal muscle (about 40% of total weight in fit men), followed by water and organs.
Note: LBM is not the same as muscle mass. Muscle is a subset of LBM along with bone, water, and organs. But since muscle is the largest variable component, LBM changes mostly reflect muscle changes.
LBM Formulas Used
This calculator uses the Boer formula, which estimates LBM from height and weight:
Males: LBM = 0.407 × weight(kg) + 0.267 × height(cm) − 19.2
Females: LBM = 0.252 × weight(kg) + 0.473 × height(cm) − 48.3
Typical LBM Ranges
| Category | Men | Women |
|---|---|---|
| Body Fat % | 10-20% | 18-28% |
| LBM as % of Weight | 80-90% | 72-82% |
| Athlete LBM % | 85-95% | 78-88% |
Using LBM for Nutrition
Many dietitians recommend basing protein intake on LBM rather than total body weight. A 250-lb person at 35% body fat has about 162 lbs of LBM. Recommending 1g protein per pound of total weight (250g) is excessive and hard to achieve. But 1g per pound of LBM (162g) is both achievable and physiologically adequate.
BMR calculations based on LBM (like the Katch-McArdle formula) are more accurate than weight-based formulas for people who are significantly over or under average body composition.
Tracking LBM Over Time
If your weight drops 10 lbs while your LBM stays the same, you lost 10 lbs of pure fat. If LBM dropped by 3 lbs, you lost 7 lbs of fat and 3 lbs of muscle. The goal during a diet: preserve as much LBM as possible. High protein intake, resistance training, and moderate calorie deficits are the three tools for that.