Add fitbit nutrition sensors (#101626)

* Add fitbit nutrition sensors

* Add test coverage for unit systems

homeassistant/components/fitbit/sensor.py

@@ -33,6 +33,7 @@ from homeassistant.const import (
     UnitOfLength,
     UnitOfMass,
     UnitOfTime,
+    UnitOfVolume,
 )
 from homeassistant.core import HomeAssistant
 from homeassistant.data_entry_flow import FlowResultType
@@ -122,6 +123,13 @@ def _elevation_unit(unit_system: FitbitUnitSystem) -> UnitOfLength:
     return UnitOfLength.METERS
 
 
+def _water_unit(unit_system: FitbitUnitSystem) -> UnitOfVolume:
+    """Determine the water unit."""
+    if unit_system == FitbitUnitSystem.EN_US:
+        return UnitOfVolume.FLUID_OUNCES
+    return UnitOfVolume.MILLILITERS
+
+
 @dataclass
 class FitbitSensorEntityDescription(SensorEntityDescription):
     """Describes Fitbit sensor entity."""
@@ -453,6 +461,24 @@ FITBIT_RESOURCES_LIST: Final[tuple[FitbitSensorEntityDescription, ...]] = (
         state_class=SensorStateClass.TOTAL_INCREASING,
         entity_category=EntityCategory.DIAGNOSTIC,
     ),
+    FitbitSensorEntityDescription(
+        key="foods/log/caloriesIn",
+        name="Calories In",
+        native_unit_of_measurement="cal",
+        icon="mdi:food-apple",
+        state_class=SensorStateClass.TOTAL_INCREASING,
+        scope="nutrition",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
+    FitbitSensorEntityDescription(
+        key="foods/log/water",
+        name="Water",
+        icon="mdi:cup-water",
+        unit_fn=_water_unit,
+        state_class=SensorStateClass.TOTAL_INCREASING,
+        scope="nutrition",
+        entity_category=EntityCategory.DIAGNOSTIC,
+    ),
 )
 
 # Different description depending on clock format