What Is Intermittent Fasting

Intermittent fasting (IF) is a diet that cycles between periods of voluntary fasting or reduced calorie intake and non-fasting over a given period, with methods including alternate-day fasting, periodic fasting, and daily time-restricted eating. There are several methods of intermittent fasting, including alternate-day fasting, periodic fasting, and daily time-restricted eating, as discussed by some sources. Originating from ancient practices, intermittent fasting has been classified as a diet and a subclass of fasting.