I have been doing the Fast Diet for a couple of years now. It works wonderfully, without having to buy any special equipment or supplement, which is fantastic. However, even after all this time, the diet days still need getting some use to. This is especially true when I am on "maintenance" mode, which means you fast once instead of twice a week. Because I am doing it less frequently, the diet day becomes harder because the body takes more time to adjust. Some time back, I came across an article talking about Circadian Rhythm Fasting , popularized by Dr Jason Fung and many others. Here's a more recent article on the topic. The main idea is to restrict eating to a small window of the day, effectively fasting for the rest of the time. Like the Fast Diet, it does not require any special equipment or supplement, and is very flexible with the timing. For example, you can choose to start at 7am and end at 3pm, or start at 12pm and end at 6pm. However, the common guideline