s-shemmee / Calories-Calculator-Python

Simple python script to calculate your Basal Metabolic Rate (BMR)! Find out how many calories you need per day to maintain your current weight.

Calories Python Calculator

Mifflin St. Guyer's equation

The Mifflin-St Jeor formula, the most reliable and accurate equation, according to the systematic review published by the Journal of the Academy of Nutrition and Dietetics in 2005, this equation depends on a group of elements, namely; Age, height, and weight, in addition to gender, the mathematical formulas used to calculate the basal metabolic rate (BMR) for males and females, as follows:

Defining Main Function

def main():
    welcome()
    gender = sex()
    weight = get_weight()
    height = get_height()
    age = get_age()
    rest_bmr = calculate_bmr(gender, weight, height, age) 
    total_calculation(rest_bmr)

Little introduction

def welcome():
    print("Welcome to your calories python calculator!\nFind out How many calories should you eat daily.\n")

Ask for user gender

def sex():    
    sexes = ["male","female","M","F","f","m","Male","Female"]
    while True:
        sex = str(input("Do you identify as male or female? "))
        while sex not in sexes:
            sex = str(input("Please enter either 'male' or 'female' "))
        else:
            return sex
            break

Get user weight in Kg

def get_weight():
    weight_kg = float(input("Enter your weight in kilograms: "))
    while weight_kg <= 0:
        weight_kg = float(input("Invalid input. Please enter your weight in kilograms: "))
    else:
        return weight_kg

Get user Height in Cm

def get_height():
    height_cm = float(input("Enter your height in Centimeters: "))
    while height_cm <= 0:
        height_cm = float(input("Invalid input. Please enter your height in Centimeters: "))
    else:
        return height_cm

Get user age in years

def get_age():
    age_yrs = int(input("Enter your age in years: "))
    while age_yrs <= 0:
        age_yrs = int(input("Invalid Input. Please enter your age in years: "))
    else:
        return age_yrs

BMR calculations for male or female

def calculate_bmr(gender, weight, height, age):
    male = ["male", "M" , "m", "Male"]
    female = ["female", "F", "f", "Female"]
    if gender == female:
        women = (weight * 10) + (height * 6.25) - (age * 5) - 161
        return int(women)
    else:
        men = (weight * 10) + (height * 6.25) - (age * 5) + 5
        return int(men)

calculate total daily calories based on bmr and and activity level

def total_calculation(rest_bmr):
    user_activity_lvl = get_user_activity()    

    maintain = {
      "sedentary" : get_sedentary(rest_bmr), 
      "light" : get_light_activity(rest_bmr), 
      "moderate" : get_moderate_activity(rest_bmr), 
      "active" : get_very_active(rest_bmr)
      }

    if user_activity_lvl == "sedentary":
        print("You need to eat " + str(maintain["sedentary"]) + " calories a day to maintain your current weight")

    if user_activity_lvl == "light":
        print("You need to eat " + str(maintain["light"]) + " calories a day to maintain your current weight")

    if user_activity_lvl == "moderate":
        print("You need to eat " + str(maintain["moderate"]) + " calories a day to maintain your current weight")

    if user_activity_lvl == "active":
        print("You need to eat " + str(maintain["active"]) + " calories a day to maintain your current weight")

Get user weekly activity levels

def get_user_activity():
    activity_lvl = ["sedentary", "light", "moderate", "active"]
    while True:
        user_lvl = str(input("\nWhat is your activity level?\n\nSedentary is little to no exercise.\nLightly active is light exercise/sports 1 - 3 days/week.\nModerately active is moderate exercise/sports 3 - 5 days/week.\nVery active is hard exercise every day, or 2 xs/day 6 - 7 days/week.\n\nPlease enter: 'sedentary', 'light', 'moderate',  or 'active' "))
        
        while user_lvl not in activity_lvl:
            user_lvl = str(input( "Invalid input. Please enter: 'sedentary', 'light', 'moderate',  or 'active' "))
        else:
            return user_lvl
            break

Multiply resting BMR by Activity levels

def get_sedentary(rest_bmr):
    sedentary = rest_bmr * 1.25
    return sedentary

def get_light_activity(rest_bmr):
    light = rest_bmr * 1.375
    return light

def get_moderate_activity(rest_bmr):
    moderate = rest_bmr * 1.550
    return moderate

def get_very_active(rest_bmr):
    active = rest_bmr * 1.725
    return active

In Python “if__name__== “__main__” allows you to run the Python files either as reusable modules or standalone programs.

if __name__ == '__main__':
    main()