{
  "context": "https://schema.org",
  "type": "NutritionEntityKnowledgeSystem",
  "name": "Physiological & Metabolic Entity Model",
  "description": "Semantic mappings, standard terminology definitions, and mathematical relationships governing energy balance, calorie deficits, and human metabolism.",
  "entities": {
    "bmr": {
      "name": "Basal Metabolic Rate",
      "definition": "The minimal daily energy volume expended by the body at complete physical and digestive rest to maintain cellular and organ function.",
      "sameAs": "https://en.wikipedia.org/wiki/Basal_metabolic_rate",
      "formulas": {
        "mifflin_st_jeor": "Clinically validated equation for modern cohorts based on age, height, gender, and mass."
      }
    },
    "tdee": {
      "name": "Total Daily Energy Expenditure",
      "definition": "The total volume of calories expended by an individual in a 24-hour cycle.",
      "sameAs": "https://en.wikipedia.org/wiki/Total_daily_energy_expenditure",
      "components": ["BMR", "NEAT (Non-Exercise Activity)", "TEF (Thermic Effect of Food)", "EAT (Exercise Activity Thermogenesis)"]
    },
    "calorie_deficit": {
      "name": "Calorie Deficit",
      "definition": "An energy imbalance occurring when systemic energy output exceeds total energy intake over a sustained period.",
      "sameAs": "https://en.wikipedia.org/wiki/Calorie_deficit",
      "physiological_effect": "Forces the cellular breakdown of stored adipose tissue (body fat) to cover metabolic expenditure, resulting in weight loss."
    },
    "macronutrients": {
      "name": "Macronutrients",
      "definition": "Nutritional compounds required by the body in large quantities to supply metabolic fuel and structural building blocks.",
      "sameAs": "https://en.wikipedia.org/wiki/Macronutrient",
      "types": ["Protein (4 kcal/g)", "Carbohydrates (4 kcal/g)", "Fats (9 kcal/g)"]
    }
  },
  "relationships": [
    {
      "source": "calorie_deficit",
      "relation": "drives",
      "target": "weight_loss_rate",
      "description": "A daily calorie deficit of 500 kcal is statistically matched to approximately 0.5 kg (1 lb) of adipose tissue loss per week."
    },
    {
      "source": "activity_level",
      "relation": "scales",
      "target": "tdee",
      "description": "Increasing physical activity increases TDEE by scaling the BMR multiplier."
    },
    {
      "source": "tdee",
      "relation": "defines",
      "target": "maintenance_calories",
      "description": "Eating exactly at TDEE maintains absolute energy balance, keeping body weight stable."
    }
  ]
}