Analyze and Report on Weight Loss Data

Weightloss Analyzer analyzes weight-loss data, calculates metabolic rate, tracks energy deficits, and manages weight-loss phases. It covers four functions: (1) Body composition analysis - BMI calculation and WHO Asian-standard classification (underweight <18.5, normal 18.5-24, overweight 24-28, obese >=28), body fat percentage assessment (male: 15-20% normal, >25% obese; female: 20-25% normal, >30% obese), waist and waist-hip ratio analysis for abdominal obesity risk, and ideal weight via both the BMI method and the Broca formula; (2) Metabolic rate calculation using three BMR formulas - the original 1919 Harris-Benedict, the recommended and more accurate Mifflin-St Jeor, and the lean-mass-based Katch-McArdle - then TDEE via BMR multiplied by an activity factor (1.2 sedentary through 1.9 very active); (3) Energy deficit management - daily deficit tracking (TDEE minus actual intake plus exercise burn), weight-loss estimation (1kg fat is approximately 7700 kcal), and safe deficit boundaries (500-1000 kcal/day for 0.5-1kg/week loss, with minimum intake floors of 1500 kcal/day for men and 1200 kcal/day for women, never below BMR x 1.2); (4) Phase management - tracking the active weight-loss phase, detecting plateaus (2+ weeks with less than 0.5kg change, attributed to metabolic adaptation, water retention, or muscle gain, addressed via calorie adjustment/exercise variation/intermittent fasting), and a maintenance phase keeping weight within +/-2kg of target with periodic monitoring.

Use it when analyzing weight-loss data, metabolic rate, energy deficits, or weight-loss phase management, when the task involves BMI/body fat/measurements/BMR/TDEE, or when the user requests progress evaluation, goal planning, or personalized weight-loss recommendations.

Reads from a fitness tracker (data/fitness-tracker.json: weight records, body composition, metabolic rate, phase management), a nutrition tracker (data/nutrition-tracker.json: calorie intake, energy deficits, meal plans), and daily health logs (data/health-logs/YYYY-MM/YYYY-MM-DD.json). Outputs four report types: a body composition report (BMI, body fat %, waist/hip measurements, recommendations); a metabolic rate report comparing all three BMR formulas side by side with a recommended value, TDEE, and three deficit-tier calorie targets (mild/aggressive/rapid, the last flagged short-term-only); a weekly energy deficit tracking report with a per-day intake/exercise/deficit table, average deficit, days-on-target, and projected weight loss; and a phase management report tracking progress percentage, weekly loss rate trend, and explicit plateau status. Invoked via /fitness:weightloss-* and /nutrition:weightloss-* commands (setup, bmr, track, report, plateau-check).

Safety principles are hard-coded: minimum 1200 kcal/day for women and 1500 kcal/day for men, absolute floor of BMR x 1.2, safe loss rate of 0.5-1kg/week (never exceeding 1.5kg/week). A medical disclaimer states the skill is for health reference only, not medical advice, and lists conditions requiring a doctor's consultation: BMI over 35, chronic disease (heart disease, hypertension, diabetes), prescription medication use, pregnancy or breastfeeding, or any uncertain health condition.

Individuals tracking their own weight-loss progress who want formula-based BMR/TDEE calculations and structured deficit/plateau reporting rather than generic calorie advice - always within the skill's explicit safety boundaries and medical-consultation triggers.