It's not just a fasting timer like many other apps (where you simply mark fasting start and finish). In fact, it's a timer for both fasting and eating windows. Not only shows when you can already break your fasting, but also helps to plan the day by calculating the latest time when you can start your second meal and still stay in the eating window. Practical usefulness and a lot of fun - for both new and experienced intermittent fasters. IntFast will become an inseparable part of your keto life! No registration and account, no email needed - just install and use. The app is very simple - it has only one button! The text in the button changes throughout the day, showing "START MEAL 1", "FINISH MEAL 1", "START MEAL 2" or "FINISH MEAL 2". You only need to abide by one important rule - the Traffic Lights Rule: * You can eat only when the timers are in green color. * When the timers are red, eating is prohibited. The full 16:8 cycle consists of 4 time periods: * "FASTING WINDOW" * "MEAL 1" * "AFTER MEAL 1" (i.e. the gap between the meals) * "MEAL 2" Obviously, the last 3 periods make up the "EATING WINDOW". The app has two timers: * The upper timer counts the duration of the meals, and of the gap between them. Shown only during the EATING WINDOW. * The lower timer counts the duration of the current WINDOW (be it FASTING or EATING). The app is customizable. In the Settings screen, you can pre-program the following 3 time periods (which correspond to the first 3 rules described here: http://intfast.ca/instruction-how-to-start-intermittent-fasting/): * Maximum EATING WINDOW (4, 5, 6, 7 or 8 hours). So, the protocols 20:4, 19:5, 18:6 and 17:5 are supported as well. * Maximum meal duration (15, 20, 25, 30, 35 or 40 minutes). * Minimum gap between meals (3, 4 or 5 hours). These settings are taken into account by the informative messages which help you to plan your day. For example, when you are in between meals or fasting, the app says how much time you have to wait until the next meal, and displays the EARLIEST time when you can start it. In between the meals, it also displays the LATEST time when you can start MEAL 2 and still stay in the EATING WINDOW. Anecdotally, that message was initially intended as an additional service, but during the app testing, that feature was found to be even more important and useful than the timers themselves! More details and FAQ: http://intfast.ca/intermittent-fasting-timer-app-android/