Calorie deficit weight-change projection API

Project weight change from a calorie deficit/surplus using the 7700-kcal-per-kg rule (weightChangeKg = (intake − maintenance)·days / 7700), with weekly rate and a safety note. Answers 'how much weight will I lose in a 500 kcal deficit', 'weight change from eating 1900 vs 2400 kcal', 'calorie deficit calculator'.

Price$0.01per request

MethodPOST

Route/v1/health/calorie-deficit

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

healthcalorie-deficitweight-losscaloriesdietdeficitsurpluscalculator

API URLhttps://x402.hexl.dev/v1/health/calorie-deficit

Integration docs

Example request

{
  "maintenanceKcal": 2400,
  "intakeKcal": 1900,
  "days": 7
}

Example response

{
  "dailyDeltaKcal": -500,
  "direction": "deficit",
  "weeklyWeightChangeKg": -0.455,
  "projectedWeightChangeKg": -0.455,
  "days": 7,
  "formula": "weightChangeKg = (intake - maintenance) * days / 7700",
  "inputs": {
    "maintenanceKcal": 2400,
    "intakeKcal": 1900
  },
  "note": "Within a sustainable range."
}

Input schema

{
  "type": "object",
  "required": [
    "maintenanceKcal",
    "intakeKcal"
  ],
  "properties": {
    "maintenanceKcal": {
      "type": "number",
      "examples": [
        2400
      ]
    },
    "intakeKcal": {
      "type": "number",
      "examples": [
        1900
      ]
    },
    "days": {
      "type": "number",
      "default": 7,
      "examples": [
        7
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}