Ideal weight: drop Broca family and Hamwi

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2026-11-10 16:48:51 +01:00 · 2026-11-01 18:54:38 +01:00 · 2026-11-01 18:54:38 +01:00 · bda76b495d
commit bda76b495d
parent 8957d51432
10 changed files with 35 additions and 154 deletions
--- a/app/lib/services/body_calc.dart
+++ b/app/lib/services/body_calc.dart
@ -41,11 +41,6 @@ const String trefethenNote =
    "Trefethen's new BMI = 1.3 x kg / m^2.5: corrects classic BMI, which "
    'over-reads tall people and under-reads short ones.';

-/// Broca explained, shown under the ideal-weight list.
-const String brocaNote =
-    'Broca = height in cm - 100 (1871); it overshoots, so Broca (modified) '
-    'takes 10% off it for men and 15% for women.';
-
 /// The lean-mass formula the calorie table switches to with a body fat %.
 const String katchMcArdle = 'Katch-McArdle';

@ -150,8 +145,9 @@ double? _perInch(

 /// Every ideal-body-weight formula we can evaluate, in kg.
 ///
-/// Only Creff uses age. The BMI healthy range is [healthyRange], shown with
-/// BMI; [idealSummary] averages these.
+/// Only data-backed ones (Devine, its MetLife refits, Peterson); Broca, its
+/// derivatives and Hamwi were dropped. The BMI healthy range is
+/// [healthyRange], shown with BMI; [idealSummary] averages these.
 List<Formula> idealWeights(Biometrics bio) {
  final h = bio.heightCm;
  final inches = h / _cmPerInch - _fiveFeetIn;
@ -168,14 +164,6 @@ List<Formula> idealWeights(Biometrics bio) {
      'Miller',
      _perInch(inches, male ? 56.2 : 53.1, male ? 1.41 : 1.36, defined: ok),
    ),
-    Formula(
-      'Hamwi',
-      _perInch(inches, male ? 48 : 45.5, male ? 2.7 : 2.2, defined: ok),
-    ),
-    Formula('Broca', h - 100.0),
-    Formula('Broca (modified)', (h - 100.0) * (male ? 0.9 : 0.85)),
-    Formula('Lorentz', h - 100.0 - (h - 150.0) / (male ? 4.0 : 2.0)),
-    Formula('Creff (age)', (h - 100.0 + bio.ageYears / 10.0) * 0.9),
    Formula(
      'Peterson (BMI 22)',
      2.2 * _targetBmi + 3.5 * _targetBmi * (metres - 1.5),
--- a/app/lib/widgets/body/body_stats_cards.dart
+++ b/app/lib/widgets/body/body_stats_cards.dart
@ -66,10 +66,9 @@ class IdealWeightCard extends StatelessWidget {
            '${oneDecimal(summary.$2)}-${oneDecimal(summary.$3)} kg',
          ),
        ],
-        const BodyNote(brocaNote),
        if (undefined)
          const BodyNote(
-            'Devine, Robinson, Miller and Hamwi are undefined below 152.4 cm.',
+            'Devine, Robinson and Miller are undefined below 152.4 cm.',
          ),
      ],
    );
--- a/app/pubspec.yaml
+++ b/app/pubspec.yaml
@ -2,7 +2,7 @@ name: diet_guard_app
 description: "Companion phone app for diet_guard: log meals on the go."
 publish_to: 'none'

-version: 1.0.122+1
+version: 1.0.123+1

 environment:
  sdk: ^3.12.2
--- a/app/test/screens/body_screen_test.dart
+++ b/app/test/screens/body_screen_test.dart
@ -71,7 +71,7 @@ void main() {
    expect(find.text('24.7'), findsOneWidget);
    expect(find.text('59.9-80.7 kg'), findsOneWidget);
    expect(find.text('Average of all'), findsOneWidget);
-    expect(find.textContaining('Broca = height'), findsOneWidget);
+    expect(find.textContaining('Broca'), findsNothing);
    expect(find.text('1780 kcal'), findsOneWidget);
    expect(find.text('n/a -- log a body-fat %'), findsNWidgets(2));
    // 5000 steps over baseline x 0.747 m x 0.5 x 80 kg = 149.4 kcal, and
--- a/app/test/widgets/body/body_widgets_test.dart
+++ b/app/test/widgets/body/body_widgets_test.dart
@ -77,7 +77,7 @@ void main() {
        children: [BmiCard(bio: _short), IdealWeightCard(bio: _short)],
      ),
    );
-    expect(find.text('n/a'), findsNWidgets(4));
+    expect(find.text('n/a'), findsNWidgets(3));
    expect(find.textContaining('undefined below 152.4 cm'), findsOneWidget);
    expect(find.text('adult categories do not apply under 20'), findsOneWidget);
  });
--- a/diet_guard/_body_calc.py
+++ b/diet_guard/_body_calc.py
@ -23,7 +23,6 @@ from diet_guard._budget_biometrics import Biometrics, mifflin_st_jeor_bmr

 __all__ = [
    "BMI_PRIME_NOTE",
-    "BROCA_NOTE",
    "KATCH_MCARDLE",
    "TREFETHEN_NOTE",
    "BmiReport",
@ -38,7 +37,7 @@ __all__ = [
 ]

 _CM_PER_INCH = 2.54
-# The inch-based formulas (Devine, Robinson, Miller, Hamwi) are all
+# The inch-based formulas (Devine, Robinson, Miller) are all
 # "base + k per inch over five feet"; below five feet they are undefined.
 _FIVE_FEET_IN = 60.0
 # Adult BMI categories are WHO's and do not apply to anyone still growing.
@ -71,10 +70,6 @@ TREFETHEN_NOTE = (
    "over-reads tall people and under-reads short ones."
 )
 KATCH_MCARDLE = "Katch-McArdle"
-BROCA_NOTE = (
-    "Broca = height in cm - 100 (1871); it overshoots, so Broca (modified) "
-    "takes 10% off it for men and 15% for women."
-)


 def half_up(value: float, digits: int = 0) -> float:
@ -140,9 +135,11 @@ def _per_inch(
 def ideal_weights(bio: Biometrics) -> tuple[Formula, ...]:
    """Every ideal-body-weight formula we can evaluate, in kg.

-    Only Creff uses age -- it is the one that answers "ideal weight for my age
-    and height". The BMI healthy range is :func:`healthy_range`, shown with
-    BMI rather than here; :func:`ideal_summary` averages these.
+    Only data-backed ones: Devine and its MetLife-table refits (Robinson,
+    Miller), and Peterson (NHANES). Broca, its derivatives (modified Broca,
+    Lorentz, Creff) and Hamwi were dropped as unvalidated rules of thumb.
+    The BMI healthy range is :func:`healthy_range`, shown with BMI rather than
+    here; :func:`ideal_summary` averages these.
    """
    h = bio.height_cm
    inches = h / _CM_PER_INCH - _FIVE_FEET_IN
@ -161,14 +158,6 @@ def ideal_weights(bio: Biometrics) -> tuple[Formula, ...]:
                inches, 56.2 if male else 53.1, 1.41 if male else 1.36, defined=ok
            ),
        ),
-        Formula(
-            "Hamwi",
-            _per_inch(inches, 48.0 if male else 45.5, 2.7 if male else 2.2, defined=ok),
-        ),
-        Formula("Broca", h - 100.0),
-        Formula("Broca (modified)", (h - 100.0) * (0.9 if male else 0.85)),
-        Formula("Lorentz", h - 100.0 - (h - 150.0) / (4.0 if male else 2.0)),
-        Formula("Creff (age)", (h - 100.0 + bio.age_years / 10.0) * 0.9),
        Formula(
            "Peterson (BMI 22)", 2.2 * _TARGET_BMI + 3.5 * _TARGET_BMI * (metres - 1.5)
        ),
--- a/diet_guard/_body_report.py
+++ b/diet_guard/_body_report.py
@ -16,7 +16,7 @@ from diet_guard._activity_kcal import (
    METHODS_NOTE,
    session_kcal,
 )
-from diet_guard._body_calc import BMI_PRIME_NOTE, BROCA_NOTE, TREFETHEN_NOTE, half_up
+from diet_guard._body_calc import BMI_PRIME_NOTE, TREFETHEN_NOTE, half_up
 from diet_guard._body_energy import KCAL_PER_KG, MIN_TARGET_KCAL, activity_label
 from diet_guard._body_steps import STEP_BASELINE
 from diet_guard._body_store import age_on
@ -114,7 +114,6 @@ def ideal_lines(view: BodyView) -> list[str]:
        avg, low, high = summary
        lines.append(f"  {'Average of all':<{_NAME_W}}{_num(avg, 1)} kg")
        lines.append(f"  {'Ideal range':<{_NAME_W}}{_num(low, 1)}-{_num(high, 1)} kg")
-    lines.extend(_wrap(BROCA_NOTE, "  "))
    return lines


--- a/diet_guard/tests/test_body_calc.py
+++ b/diet_guard/tests/test_body_calc.py
@ -18,6 +18,7 @@ from diet_guard._body_calc import (
    bmr_formulas,
    half_up,
    ideal_summary,
+    ideal_weights,
    table_bmr,
 )
 from diet_guard._body_energy import (
@ -81,6 +82,11 @@ class TestBmr:
    def test_ideal_summary_is_none_when_nothing_applies(self) -> None:
        assert ideal_summary(()) is None

+    def test_only_data_backed_ideal_weight_formulas(self) -> None:
+        # Broca, its derivatives and Hamwi are unvalidated rules of thumb.
+        names = tuple(f.name for f in ideal_weights(_MAN))
+        assert names == ("Devine", "Robinson", "Miller", "Peterson (BMI 22)")
+

 class TestGoal:
    def test_kg_per_day_signs(self) -> None:
--- a/docs/DOCS-body.md
+++ b/docs/DOCS-body.md
@ -115,8 +115,8 @@ every formula's daily total. Heart-rate input was dropped at the user's call.
 ## Calculations (`_body_calc.py`, `_body_energy.py`, `_week_plan.py`)

 - **BMI** kg/m², BMI Prime, Trefethen; WHO bands, not applied under 20.
- **Ideal weight**: Devine, Robinson, Miller, Hamwi (undefined < 152.4 cm),
-  Broca, modified Broca, Lorentz, Creff (the one that uses age), Peterson;
+- **Ideal weight**: Devine, Robinson, Miller (undefined < 152.4 cm), Peterson;
+  Broca, modified Broca, Lorentz, Creff and Hamwi were dropped (unvalidated);
  then their average and min-max "ideal range". The BMI 18.5-24.9 healthy
  range sits with BMI.
 - **BMR**: Mifflin-St Jeor, Harris-Benedict (1984), and with a body fat
--- a/tests/fixtures/body_calc.json
+++ b/tests/fixtures/body_calc.json
@ -27,26 +27,6 @@
     "Miller",
     71.5212598425197
    ],
-    [
-     "Hamwi",
-     77.33858267716536
-    ],
-    [
-     "Broca",
-     80.0
-    ],
-    [
-     "Broca (modified)",
-     72.0
-    ],
-    [
-     "Lorentz",
-     72.5
-    ],
-    [
-     "Creff (age)",
-     74.7
-    ],
    [
     "Peterson (BMI 22)",
     71.50000000000001
@ -90,9 +70,9 @@
    ]
   ],
   "ideal_summary": [
-    74.13307086614174,
+    72.66476377952756,
    71.50000000000001,
-    80.0
+    74.99212598425197
   ],
   "healthy_range": [
    59.94000000000001,
@ -361,26 +341,6 @@
     "Miller",
     59.84645669291338
    ],
-    [
-     "Hamwi",
-     56.413385826771645
-    ],
-    [
-     "Broca",
-     65.0
-    ],
-    [
-     "Broca (modified)",
-     55.25
-    ],
-    [
-     "Lorentz",
-     57.5
-    ],
-    [
-     "Creff (age)",
-     62.550000000000004
-    ],
    [
     "Peterson (BMI 22)",
     59.95
@ -424,9 +384,9 @@
    ]
   ],
   "ideal_summary": [
-    58.98359580052493,
-    55.25,
-    65.0
+    58.53474409448818,
+    56.90944881889762,
+    59.95
   ],
   "healthy_range": [
    50.366249999999994,
@ -695,26 +655,6 @@
     "Miller",
     null
    ],
-    [
-     "Hamwi",
-     null
-    ],
-    [
-     "Broca",
-     50.0
-    ],
-    [
-     "Broca (modified)",
-     42.5
-    ],
-    [
-     "Lorentz",
-     50.0
-    ],
-    [
-     "Creff (age)",
-     47.25
-    ],
    [
     "Peterson (BMI 22)",
     48.400000000000006
@ -758,9 +698,9 @@
    ]
   ],
   "ideal_summary": [
-    47.63,
-    42.5,
-    50.0
+    48.400000000000006,
+    48.400000000000006,
+    48.400000000000006
   ],
   "healthy_range": [
    41.625,
@ -1029,26 +969,6 @@
     "Miller",
     68.74566929133857
    ],
-    [
-     "Hamwi",
-     72.02362204724409
-    ],
-    [
-     "Broca",
-     75.0
-    ],
-    [
-     "Broca (modified)",
-     67.5
-    ],
-    [
-     "Lorentz",
-     68.75
-    ],
-    [
-     "Creff (age)",
-     69.03
-    ],
    [
     "Peterson (BMI 22)",
     67.65
@ -1092,9 +1012,9 @@
    ]
   ],
   "ideal_summary": [
-    69.78548556430445,
-    67.5,
-    75.0
+    68.94143700787401,
+    67.65,
+    70.46456692913384
   ],
   "healthy_range": [
    56.65625,
@ -1363,26 +1283,6 @@
     "Miller",
     77.62755905511811
    ],
-    [
-     "Hamwi",
-     89.03149606299212
-    ],
-    [
-     "Broca",
-     91.0
-    ],
-    [
-     "Broca (modified)",
-     81.9
-    ],
-    [
-     "Lorentz",
-     80.75
-    ],
-    [
-     "Creff (age)",
-     85.59
-    ],
    [
     "Peterson (BMI 22)",
     79.97
@ -1426,9 +1326,9 @@
    ]
   ],
   "ideal_summary": [
-    83.52175853018372,
+    80.85608267716535,
    77.62755905511811,
-    91.0
+    84.9527559055118
   ],
   "healthy_range": [
    67.48985,