BODY COMPOSITION
BODY FAT PERCENTAGE REFERENCE
Essential Fat: 3–5% (men) / 10–13% (women) — minimum for organ function.
Athletic: 6–13% (men) / 14–20% (women) — peak performance range.
Fitness: 14–17% (men) / 21–24% (women) — lean and healthy.
Average: 18–24% (men) / 25–31% (women) — typical for sedentary adults.
Obese: 25%+ (men) / 32%+ (women) — elevated metabolic disease risk.
Measurement methods by accuracy: DEXA scan > Hydrostatic weighing > BOD POD > Navy formula > BIA scale > BMI (least accurate).
OPTIMAL RATES OF CHANGE
Fat loss: 0.5–1% body weight per week (faster = muscle loss risk). Example: 90kg person → 450–900g/week deficit. Requires ~500–1000 kcal daily deficit.
Muscle gain (natural): ~0.5–1kg/month for beginners, ~0.25kg/month for advanced. Requires slight caloric surplus (200–300 kcal) + progressive overload + adequate protein (1.6–2.2g/kg).
Recomposition: Simultaneous fat loss + muscle gain. Possible for beginners and those returning from training. Requires precise protein + calorie targets.
THE BODY RECOMPOSITION PROTOCOL
1. Protein: 2.0–2.2g per kg of bodyweight (minimum). The single most important variable.
2. Resistance training: 3–6 sessions/week, progressive overload, compound movements.
3. Calorie intake: Slight deficit (200–300 kcal) for fat loss, or maintenance for recomp.
4. Sleep: 7–9 hours. Growth hormone peaks during SWS. Cutting sleep cuts muscle gains ~50%.
5. Stress management: High cortisol drives fat storage and muscle breakdown.
6. Weigh daily (same conditions, morning, fasted) and use 7-day average. Daily fluctuations of 1–3kg from water are normal.
WAIST-TO-HEIGHT RATIO (WHTR)
Waist circumference / Height. More predictive of cardiovascular risk than BMI. Target: <0.5 (half your height or less). <0.5 = low risk, 0.5–0.6 = increased risk, >0.6 = high risk. This single metric correlates strongly with visceral fat, insulin resistance, and cardiometabolic disease.
BMI LIMITATIONS
Body Mass Index (kg/m²) does not distinguish between fat mass and lean mass. A highly muscular athlete will register "overweight" or "obese" on BMI. It also fails to account for fat distribution — visceral (abdominal) fat is far more dangerous than subcutaneous fat, and BMI cannot detect this. Use BMI only as a broad population-level screening tool, not as an individual health metric. Combine with BF%, waist circumference, and WHTR for a complete picture.