Longer fasts
How-to notes for a stretch past a daily window: safety first, a plan, water, and an exit. A 72-hour challenge, stacked 16:8s, and a clinic at home are not the method.
A long stretch is a different practice from a daily eating window. Unlimited tracking is flexibility, not a dare. Open-ended and multi-day fasts is why this timer has no cap. These notes are for people who already mean 24 hours or more.
Forums treat 48 and 72 as the next level after 16:8. Those are extra hours and extra risk. A timer cannot clear you. Very long fasts is for people who have already chosen many days. How to make fasting easier stays with quieter daily hours. Everyday Fasting stays with drinks and daily life. Fundamentals is the main set of notes.
Educational only. Not medical advice. See our disclaimer.
Start a timer: 16:8 timer · OMAD timer · online fasting timer.
- Part 1: Before a longer fast: A stretch past a daily window is a different practice, not the next level after 16:8. Safety first, a plan you can say in one sentence, water, and an exit. A 72-hour challenge is not the start.
- Part 2: Water and minerals past a day: Past about a day, water is still what you drink. Meals are no longer replacing sodium and the other minerals, so salt becomes a louder topic in heat and after heavy sweat. Buying a salt mix does not replace the missing meal.
- Part 3: After the first day: Once food has been missing for about a day, hunger at the old meal time, feeling cooler, and lighter sleep are common reports. Dizziness, confusion, chest pain, and a heartbeat you cannot explain still mean stop.
- Part 4: What a long fast is not: Three days of 16:8 still include a meal each day. A 72-hour number is a time you planned to eat, not a test you have to pass. A phone cannot check your blood pressure or tell you to stop and eat.
Fasting Fundamentals · How to make fasting easier · Very long fasts · Using the Clock · Everyday Fasting · Questions from the community · History of Fasting · Humans, Food & Feast–Famine · What Research Suggests · Fasting, myths and science