Source: https://guthlabs.ai/docs/instruments/basal-metabolic-rate-weight-change-projector/implementation/

instrument implementation / implementation-contract

# Basal Metabolic Rate → Weight Change Projector implementation

A source-bound implementation contract for Basal Metabolic Rate → Weight Change Projector; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t5-198

**Effect**: Computation or source lookup only

## Input and validation requirements

An extreme but syntactically numeric input causes JavaScript floating-point overflow during daily_caloric_balance_kcal × duration_days, producing Infinity and therefore no valid finite projected weight. The instrument should reject or explicitly flag the result.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "daily_caloric_balance_kcal_per_day": -500,
    "duration": 14,
    "duration_unit": "days"
  },
  "expected_outputs": {
    "total_energy_delta_kcal": -7000,
    "projected_weight_change_kg": -0.9090909
  },
  "working": "1. Daily balance = -500 kcal/day. 2. Duration = 14 days. 3. Total energy change = -500 × 14 = -7000 kcal. 4. Projected weight change = -7000 ÷ 7700 = -0.9090909 kg."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/basal-metabolic-rate-weight-change-projector/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/basal-metabolic-rate-weight-change-projector/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/basal-metabolic-rate-weight-change-projector/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche5/tranche5-results.json`