Dart utils for calculating recommended calorie intake based on the Mifflin St Jeor equation

calorie_intake_calculator.dart

class ActivityLevel {
  static const NONE = const ActivityLevel._(1.0);
  static const SEDENTARY = const ActivityLevel._(1.2);
  static const LIGHT = const ActivityLevel._(1.375);
  static const MODERATE = const ActivityLevel._(1.55);
  static const NORMAL = const ActivityLevel._(1.725);
  static const VERY = const ActivityLevel._(1.9);

  static get values => [NONE, SEDENTARY, LIGHT, MODERATE, NORMAL, VERY];

  final double value;

  const ActivityLevel._(this.value);
}

enum Gender { male, female }

class Utils {

  /// https://wpcalc.com/en/mifflin-st-jeor/
  /// https://www.dummies.com/health/nutrition/how-to-calculate-your-metabolic-rate/
  static double mifflinStJeor(Gender gender, double kg, double cm, double years, ActivityLevel activityLevel) {
    return ((((10.0 * kg) + (6.25 * cm) - (5.0 * years)) + (gender == Gender.male ? 5 : -161)) * activityLevel.value).roundToDouble();
  }

  /// https://www.healthline.com/nutrition/how-many-calories-per-day
  static List<double> calculateIntakes(Gender gender, double kg, double cm, double years, ActivityLevel activityLevel) {
    double bmi = mifflinStJeor(gender, kg, cm, years, activityLevel);
    double loseWeight = (bmi * 0.8).roundToDouble();
    double loseWeightFast = (bmi * 0.6).roundToDouble();
    if (bmi < 1000 || (bmi * 0.8) < 1000 || (bmi * 0.6) < 1000) {
      bmi = bmi < 1000.0 ? 1000.0 : bmi = bmi.roundToDouble();
      loseWeight = (bmi * 0.8) < 1000 ? 1000.0 : (bmi * 0.8).roundToDouble();
      loseWeightFast = (bmi * 0.6) < 1000 ? 1000.0 : (bmi * 0.6).roundToDouble();
    }
    return [bmi, loseWeight, loseWeightFast];
  }
}