MoComposition

"The Analyzer" — "I reveal what the scale can't"

Status: ❌ Future

MoComposition will track body composition — body fat percentage, muscle mass, and related metrics.

---

Purpose

• Track body fat percentage
• Estimate lean muscle mass
• Monitor body composition changes
• Provide more meaningful progress than weight alone

---

Data Sources

Body composition can come from:

Source	Accuracy	Method
DEXA scan	Very high	Medical facility
Smart scale	Moderate	Bioelectrical impedance
Navy method	Moderate	Tape measurements
Calipers	Moderate	Skinfold measurements
Visual estimate	Low	Progress photos

---

Data Model

interface BodyComposition {
  id: string;
  userId: string;
  date: Date;

  // Core metrics
  bodyFatPercent: number;
  leanMassLbs: number;
  fatMassLbs: number;

  // Calculated
  ffmi: number;              // Fat-free mass index

  // Source
  source: CompositionSource;
  notes: string | null;

  createdAt: Date;
}

interface CompositionTrend {
  currentBodyFat: number;
  previousBodyFat: number;
  bodyFatChange: number;

  currentLeanMass: number;
  previousLeanMass: number;
  leanMassChange: number;

  trend: 'recomp' | 'bulking' | 'cutting' | 'maintaining';
}

type CompositionSource =
  | 'dexa'
  | 'smart_scale'
  | 'navy_method'
  | 'calipers'
  | 'estimate';

---

Calculations

Navy Method (from measurements)

// For men
bodyFatPercent = 495 / (1.0324 - 0.19077 * log10(waist - neck) + 0.15456 * log10(height)) - 450;

// For women
bodyFatPercent = 495 / (1.29579 - 0.35004 * log10(waist + hip - neck) + 0.22100 * log10(height)) - 450;

FFMI (Fat-Free Mass Index)

// Normalized measure of muscularity
const leanMassKg = (weight * (1 - bodyFatPercent / 100)) / 2.205;
const heightM = height / 100;
const ffmi = leanMassKg / (heightM * heightM) + 6.1 * (1.8 - heightM);

// FFMI ranges (men)
// 18-20: Average
// 20-22: Above average
// 22-25: Excellent
// 25+: Elite/suspicious

---

Planned API Endpoints

Endpoint	Method	Description
/api/composition	GET	Get composition history
/api/composition	POST	Log composition
/api/composition/calculate	POST	Calculate from measurements

---

Integration Points

Will Receive from:

• Smart scale import (MoWearables)
• MoMeasure (Navy method calculation)
• Manual entry

Will Provide to:

• Progress page (composition charts)
• MoGoals (body fat goals)
• MoCoach (training recommendations)

---

Implementation Tasks

• Create body_composition table
• Implement Navy method calculator
• Build composition logging UI
• Create composition charts
• Integrate with smart scale (MoWearables)
• Add FFMI calculation and display