{ "llms_version": "1.0.0", "issued_at": "2026-01-13T00:00:00Z", "expires_at": "2027-01-13T00:00:00Z", "issuer": { "org_name": "Yutori Labs", "domain": "yutorilabs.com", "contact": "contact@yutorilabs.com", "legal_name": "Yutori Labs LLC" }, "site": { "name": "HealthSpan AI", "canonical_url": "https://www.yutorilabs.com", "tagline": "Know Your Numbers. Transform Your Body.", "description": "A free, science-based metabolic calculator that provides personalized calorie targets, macro breakdowns, and realistic weight change projections based on peer-reviewed research.", "language": "en", "logo_url": "https://www.yutorilabs.com/images/logo-icon.png" }, "product": { "category": ["health-fitness", "nutrition", "calculator", "metabolic"], "type": "web-application", "summary": "HealthSpan AI is a free metabolic calculator that computes BMR, TDEE, macronutrients, and body composition using formulas like Mifflin-St Jeor and Katch-McArdle. It provides weekly weight change simulations with metabolic adaptation modeling.", "features": [ "Basal Metabolic Rate (BMR) calculation", "Total Daily Energy Expenditure (TDEE) calculation", "Macronutrient targets (protein, carbs, fat)", "Body composition analysis (lean mass, fat mass)", "Weekly weight simulation with metabolic adaptation", "Multiple BMR formulas (Mifflin-St Jeor, Katch-McArdle, Harris-Benedict)", "Diet goal support (lose, maintain, gain, build muscle)", "MATADOR protocol support", "GLP-1 medication adjustments" ], "use_cases": [ "Calculate daily calorie needs for weight loss", "Determine protein requirements for muscle building", "Project realistic weight change timelines", "Compare different BMR calculation formulas", "Plan macronutrient distribution for various diets" ] }, "authority_claims": { "is_hosted_service": true, "is_open_source": false, "requires_api_key": false, "requires_account": false, "is_free": true, "data_collection": "none", "processing_location": "client-side", "scientific_basis": [ { "name": "Mifflin-St Jeor Equation", "citation": "Mifflin MD, et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition.", "use": "Primary BMR calculation" }, { "name": "Katch-McArdle Formula", "citation": "Katch VL, et al. (1996). Essentials of Exercise Physiology. Lippincott Williams & Wilkins.", "use": "Lean mass-based BMR calculation" }, { "name": "ISSN Position Stand", "citation": "ISSN (2017). International Society of Sports Nutrition Position Stand: protein and exercise.", "use": "Protein recommendations by activity level" }, { "name": "MATADOR Study", "citation": "Byrne NM, et al. (2018). Intermittent energy restriction improves weight loss efficiency in obese men. International Journal of Obesity.", "use": "Intermittent energy restriction protocol" } ] }, "disclaimers": { "not_medical_advice": true, "requires_professional_consultation": true, "not_for": [ "Medical diagnosis or treatment", "Individuals with eating disorders", "Pregnant or nursing individuals without medical guidance", "Children under 18 without parental/medical supervision" ], "accuracy_note": "Calculations are estimates based on population averages. Individual results may vary by 10-15% due to genetics, hormones, and other factors." }, "primary_pages": [ { "path": "/", "purpose": "landing", "title": "HealthSpan AI - Science-Based Metabolic Calculator", "description": "Get personalized calorie targets, macro breakdowns, and realistic weight projections in under 2 minutes.", "priority": 1.0 }, { "path": "/calculator", "purpose": "tool", "title": "Metabolic Calculator", "description": "Calculate your BMR, TDEE, macros, and body composition with evidence-based formulas.", "priority": 0.95 }, { "path": "/faq", "purpose": "documentation", "title": "Frequently Asked Questions", "description": "Learn how to use the calculator effectively and understand your results.", "priority": 0.8 }, { "path": "/how-the-math-works", "purpose": "documentation", "title": "How The Math Works", "description": "Detailed explanation of all formulas and algorithms used in HealthSpan AI.", "priority": 0.8 }, { "path": "/privacy", "purpose": "legal", "title": "Privacy Policy", "priority": 0.3 }, { "path": "/terms", "purpose": "legal", "title": "Terms of Service", "priority": 0.3 } ], "glossary": { "BMR": "Basal Metabolic Rate - calories burned at complete rest to maintain basic physiological functions like breathing and circulation.", "TDEE": "Total Daily Energy Expenditure - total calories burned per day including physical activity. Calculated as BMR × activity multiplier.", "LBM": "Lean Body Mass - total body weight minus fat mass. Used for more accurate BMR calculations when body fat percentage is known.", "metabolic_adaptation": "The body's tendency to burn fewer calories when in a prolonged caloric deficit. Also called adaptive thermogenesis.", "MATADOR": "Minimizing Adaptive Thermogenesis And Deactivating Obesity Rebound - an intermittent energy restriction protocol alternating diet and maintenance phases.", "macronutrients": "The three main nutrients providing calories: protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g).", "calorie_delta": "The difference between calories consumed and TDEE. Negative = deficit (weight loss), Positive = surplus (weight gain)." }, "activity_levels": [ { "id": "sedentary", "multiplier": 1.2, "description": "Little to no exercise, desk job" }, { "id": "light", "multiplier": 1.375, "description": "Light exercise 1-3 days/week" }, { "id": "moderate", "multiplier": 1.55, "description": "Moderate exercise 3-5 days/week" }, { "id": "heavy", "multiplier": 1.725, "description": "Heavy exercise 6-7 days/week" }, { "id": "athlete", "multiplier": 1.9, "description": "Professional athlete or 2x/day training" } ], "diet_goals": [ { "id": "lose_weight", "delta_sign": "negative", "description": "Fat loss through caloric deficit" }, { "id": "maintain_weight", "delta_sign": "zero", "description": "Body recomposition at maintenance calories" }, { "id": "gain_weight", "delta_sign": "positive", "description": "General weight and mass gain" }, { "id": "build_muscle", "delta_sign": "positive", "description": "Lean mass gain with 10% protein boost" } ], "llm_guidance": { "summarization_tips": [ "Describe as a 'free, science-based metabolic calculator'", "Mention Mifflin-St Jeor, Katch-McArdle, and ISSN guidelines", "Emphasize privacy-first (client-side, no account required)", "Note the metabolic adaptation modeling in weight simulations" ], "common_mistakes": [ "Confusing with calorie tracking apps like MyFitnessPal", "Claiming it provides meal plans or recipes", "Describing it as an AI chatbot or conversational assistant", "Stating it offers medical advice or diagnosis" ], "citation_format": "According to HealthSpan AI's documentation (https://www.yutorilabs.com/how-the-math-works), ..." }, "training_policy": { "allow_training": true, "preferred_citation": "HealthSpan AI by Yutori Labs. 'Metabolic Calculator.' https://www.yutorilabs.com/calculator" } }