During the fasting periods you can not take in any calories, but you can take non-calorie beverages including tea, coffee, water and it has to have no sugar, dairy, or artificial sweeteners
This method is where you eat only within an 8 hour period each day and fast for the remaining 16 hours. When you’re fasting you cant take in any calories but also includes the 8 hours of sleep you get.
This method is where you eat normally for 5 days of the week, and restrict your calories to 500 (women) or 600 (men) the other 2 days. (preferably with a 2,500 or healthy daily calorie intake).
This Method is where you do one or two 24 hour fast each week; for example not eating after lunch until lunch the next day
This method is where it involves eating “normally” (definitely within reason) one day, and then eating very low calories (500-600 regardless of gender) the following day