📏 शारीरिक माप

शरीर वसा प्रतिशत

What Is It?

शरीर वसा प्रतिशत is the portion of your total weight that is composed of adipose tissue (fat). It is considered the truest metric of "Body Composition," distinguishing between poundage that is functional structure (muscle, bone, water) vs. energy storage (fat).

Essential vs. Storage Fat

  • Essential Fat: Necessary for life (hormone production, vitamin absorption, temperature regulation).
    • Men: ~2-5%
    • Women: ~10-13% (higher due to reproductive needs)
  • Storage Fat: Accumulated energy reserves in adipose tissue.

How HealthKit Measures It

Apple Watch does not measure body fat. HealthKit receives this data from: * Smart Scales: (e.g., Withings, Garmin, Qardio) which use Bioelectrical Impedance Analysis (BIA). * Manual Entry: From DEXA scans or caliper tests.

वैज्ञानिक पृष्ठभूमि

The "Obesity" Crisis of परिभाषाs

A person can have a "Normal" BMI but high body fat (low muscle mass), a condition known as sarcopenic obesity. Conversely, athletes can have an "Obese" BMI with low body fat.

Measuring body fat percentage bypasses these errors.

संदर्भ रेंज (Gallagher et al., AJCN)

Healthy ranges vary significantly by age and sex. The following are widely accepted clinical ranges:

Women: | Age | Unhealthy (Too Low) | Healthy | Overweight | Obese | | :--- | :--- | :--- | :--- | :--- | | 20-39 | < 21% | 21-32% | 33-38% | > 39% | | 40-59 | < 23% | 23-33% | 34-39% | > 40% | | 60-79 | < 24% | 24-35% | 36-41% | > 42% |

Men: | Age | Unhealthy (Too Low) | Healthy | Overweight | Obese | | :--- | :--- | :--- | :--- | :--- | | 20-39 | < 8% | 8-19% | 20-24% | > 25% | | 40-59 | < 11% | 11-21% | 22-27% | > 28% | | 60-79 | < 13% | 13-24% | 25-29% | > 30% |

नैदानिक महत्व

The Hormone Factory

Adipose tissue is biologically active. High body fat percentages correlate with: * Insulin Resistance: Excess free fatty acids interfere with glucose uptake. * Systemic Inflammation: Fat cells secrete pro-inflammatory cytokines (IL-6). * Hormonal Imbalance: Increased conversion of testosterone to estrogen (aromatization).

The "Athletic" Trap

Extremely low body fat is also dangerous. * Women (<10-13%): Risk of amenorrhea (loss of period), bone density loss, and hormonal crash (Female Athlete Triad). * Men (<2-5%): Testosterone drop, immune suppression, and fatigue.

सिफारिशें

How to Measure

  • Consistency: Bioelectrical Impedance (smart scales) is notoriously finicky. Hydration levels change the result.
  • The Rule: Measure at the same time, under the same conditions (e.g., morning, fasted, after toilet, before shower).
  • Trend > Number: The absolute number might be off by 3-5%, but if the trend is going down, you are losing fat.

Improving Body Composition

Losing weight is easy; losing fat while keeping muscle is the goal. * Strength Training: Essential to signal the body to keep muscle. * Protein Intake: High protein (1.6g - 2.2g per kg of bodyweight) protects lean mass during deficits. * Slow Loss: Losing >1% of body weight per week increases the risk of muscle loss.

संदर्भ

  1. Gallagher D, et al. (2000) Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index. The American Journal of Clinical Nutrition, 72(3), 694-701.
  2. American Council on Exercise (ACE). Body Fat Categorization.
  3. Kyle UG, et al. (2004) Bioelectrical impedance analysis—part I: review of principles and methods. Clinical Nutrition.

अंतिम अपडेट: जनवरी 2026