Kalorienrechner

def bmr_mifflin(weight_kg, height_cm, age, sex):
    """
    Mifflin-St Jeor BMR formula.

    Parameters:
        weight_kg - body weight in kilograms
        height_cm - height in centimetres
        age       - age in years
        sex       - 'male' or 'female'

    Returns Basal Metabolic Rate in kcal/day.
    """
    bmr = 10 * weight_kg + 6.25 * height_cm - 5 * age
    return bmr + 5 if sex == "male" else bmr - 161


ACTIVITY_MULTIPLIERS = {
    "sedentary":    1.2,   # little or no exercise
    "light":        1.375, # 1-3 days/week
    "moderate":     1.55,  # 3-5 days/week
    "active":       1.725, # 6-7 days/week
    "very_active":  1.9,   # twice/day or physical job
}


def tdee(weight_kg, height_cm, age, sex, activity_level="moderate"):
    """Total Daily Energy Expenditure = BMR × activity multiplier."""
    b = bmr_mifflin(weight_kg, height_cm, age, sex)
    return b * ACTIVITY_MULTIPLIERS[activity_level]


def macros(calories, protein_pct=0.30, carb_pct=0.40, fat_pct=0.30):
    """
    Split calories into macronutrient grams.
    Default split: 30% protein / 40% carbs / 30% fat.
    protein & carbs = 4 kcal/g; fat = 9 kcal/g.
    """
    return {
        "protein_g": calories * protein_pct / 4,
        "carbs_g":   calories * carb_pct   / 4,
        "fat_g":     calories * fat_pct    / 9,
    }


# Example: 30-year-old male, 80 kg, 175 cm, moderately active
b = bmr_mifflin(80, 175, 30, "male")
t = tdee(80, 175, 30, "male", "moderate")
m = macros(t)

print(f"BMR:            {b:.0f} kcal/day")
print(f"TDEE (moderate): {t:.0f} kcal/day")
print(f"Protein:        {m['protein_g']:.0f} g")
print(f"Carbs:          {m['carbs_g']:.0f} g")
print(f"Fat:            {m['fat_g']:.0f} g")

# Weight-loss / gain targets
print(f"\nWeight loss (-500 kcal): {t - 500:.0f} kcal/day")
print(f"Weight gain (+500 kcal): {t + 500:.0f} kcal/day")