What is intermittent fasting?

Intermittent fasting involves a period of not eating (or ‘fasting’) followed by a period of eating freely. There are several forms of intermittent fasting to choose from, including the 5:2 diet (aka 2 Day Fast), alternate day fasting (ADF), the 4:3 diet (aka 3 Day Fast) and the 16:8 diet (aka Part Day Fast). The 5:2 diet involves 2 days of fasting per week, where you lower to your calorie intake to 500 calories per day (or a quarter of your TDEE). On the other 5 days, you can eat normally, without having to count calories or monitor food intake. Alternate day fasting takes it one step further by adding a couple more fast days per week. More specifically, with alternate day fasting, you alternate between a 500-calorie fast day and a normal eating day, every other day. You can eat the meal all in one go or split it up in to mini meals. The 4:3 diet involves 3 days of fasting per week, where you lower your calorie intake to 1000 calories per day (or half of your TDEE. On the other four days, you can eat normally. The 16:8 diet (or Part Day Fast), is a little different from 5:2, 4:3 and alternate day fasting in that you fast a little bit every day. With 16:8 you are free to eat during an 8-hour window (let’s say 10am-6pm) then you would fast the rest of the day (6pm-10am). You can choose whatever 8-hour window works for you.