Calculate your lean body mass using body fat percentage, Boer formula, or James formula — and see exactly how much is fat vs. lean tissue.
Lean tissue burns 3× more calories at rest than fat tissue. A higher LBM means a naturally higher BMR — you can eat more without gaining fat.
Skeletal muscle enables movement, balance, and daily activities. Preserving LBM as you age directly protects your functional independence.
Adequate lean mass supports healthy testosterone, growth hormone, and insulin sensitivity — all of which deteriorate when LBM drops too low.
Lean body mass (LBM) is the weight of everything in your body except fat — including muscle, bone, organs, connective tissue, and water. It is calculated by subtracting fat mass from total body weight. LBM is a key indicator of metabolic health and physical fitness because it represents the metabolically active portion of your body.
Lean body mass includes all non-fat tissue: skeletal muscle, smooth muscle, cardiac muscle, bone, organs, blood, and water. Muscle mass refers specifically to skeletal (voluntary) muscle. In practice, the terms are sometimes used interchangeably, but LBM is always the broader measurement. Increasing muscle mass will increase LBM, but not vice versa — you can gain LBM through bone density improvements or hydration as well.
LBM directly influences your basal metabolic rate (BMR) — the more lean mass you carry, the more calories you burn at rest. Higher LBM is associated with better insulin sensitivity, stronger bones, improved hormonal balance, and greater functional strength as you age. Preserving LBM during weight loss is critical to avoiding the metabolic slowdown that often accompanies calorie restriction.
The most effective way to increase LBM is progressive resistance training combined with adequate protein intake (1.6–2.2g per kg of bodyweight per day). Compound movements like squats, deadlifts, and rows stimulate the most muscle growth. Sufficient sleep (7–9 hours) is essential for recovery and hormonal support of muscle synthesis. A small calorie surplus (200–300 kcal above TDEE) supports muscle gain without excessive fat accumulation.
HC Webhook sends your lean body mass, body fat, and weight data to any endpoint on a schedule — so your body composition trends are always up to date.
