A prolonged fast lasts more than 48 hours and it is very popular among people who are serious about their health. According to a study published by The New England Journal of Medicine, prolonged fast has shown to improve stress resistance, anti aging, reverse insulin resistance, long term weight loss etc. This calculator will use your basal metabolic rate as your max. calorie needs per day, which is based on the Mifflin & St. Jeor's formula.
* Your basal metabolic rate will reduce as you lose weight.
* There are 7,700 calories in 1kg of fat or 3500 calories in 1 pound of fat.
* This calculator doesn't take insulin resistance and your body's hormonal response to different types of food into consideration. The less insulin resistant you are the more fat stores your body will be able to convert into energy.
* This calculator assumes that your lean body mass stays the same, meaning no muscle loss during the process.
Select your gender and the type of units below
Female (Metric)
Use this calculator to find out how many days it would take you to reach your fat loss goal.
Your current body fat percentage
Your target body fat percentage
how many days do you plan to fast in a row
how many days in a row you plan to eat normally
your daily calorie consumption on the days you eat
The weight measured in kilogram
The height measured in centimeter
your age measured in years
Please note, that all calculators provided are for informational and educational purposes ONLY, and should NOT be taken as professional medical/dietary advice.