Table 1. Common intermittent fasting regimens.

Intermittent fasting regimen	Description
Periodic fasting	Fasting for up to 24 hours once or twice a week with ad libitum (as often as necessary or desired) food intake for the remaining days.
Time-restricted feeding	Involves eating for only 8 hours and fasting for the other 16 hours of the day.
Alternate-day fasting	Involves fasting for 24 hours with subsequent ad libitum feeding for the next 24 hours. Fasting days are typically achieved by consuming 0-25% of daily caloric needs.
The 5:2 diet	A derivative of the periodic fasting method, it involves restricting caloric intake on two non-consecutive days a week (500 kcal for women and 600 kcal for men), with sensible eating, but no formal energy restrictions on the remaining days.