Fasting Fundamentals
The main notes: what fasting is, safety, hunger, hydration, timer stages, schedules, and how to stop or eat again gently.
Educational only. Not medical advice. See our disclaimer.
Start a timer: 16:8 timer · OMAD timer · online fasting timer.
- Part 1: What is intermittent fasting?: A calm overview of intermittent fasting and time-restricted eating: what it is, common schedules, what it is not, and how to start gently.
- Part 2: Who should be careful with fasting: A clear, incomplete safety map: who should not fast unsupervised, which conditions and medicines raise risk, and why this timer cannot decide for you.
- Part 3: Choosing a starting window: How to pick a first fasting window: start near the overnight gap you already have (often 12–14 hours), then consider 16:8 if it still feels manageable. Why jumping to OMAD is usually a poor first step.
- Part 4: Hunger comes in waves: Why early hunger often peaks around usual meal times, what usually helps a mild wave, and how to tell a habit pang from a reason to stop.
- Part 5: Hydration & electrolytes while fasting: During the hours without food on a daily window, drink water. A shop packet of electrolyte powder is salt and sometimes potassium or magnesium. If you take medicine or have kidney disease, ask a clinician before you use one. We are not giving a grams-per-day target.
- Part 6: What the stages on the timer mean: How the names on this timer work: approximate hour ranges, what they are not, and how to use them calmly.
- Part 7: Sleep, stress, and your fasting window: Why the same hours can feel easy or brutal depending on sleep, stress, training, and illness, and why a rest day is part of a sustainable practice.
- Part 8: Common schedules compared (16:8, 18:6, OMAD): What 16:8, 18:6, and OMAD actually mean, how they differ from gentler 12–14 hour windows and from multi-day fasts, and why none is universally best.
- Part 9: Open-ended & multi-day fasts: Why this timer has no finish time you must pay to pass, how a stretch of one to three days differs from a daily window, and why the clock can follow a plan you already have.
- Part 10: When to stop a fast: How to end a fast you already started: warning signs, illness and life reasons, and planned stop times. Stopping is part of the practice, not a failed streak.
- Part 11: Breaking a fast gently: After a daily window, the first meal is usually an ordinary lunch. After a day or two without food, start smaller and wait before you eat more. We are not giving a menu.
- Part 12: Building a sustainable rhythm: How to keep a fasting practice useful over months: rest days, flexible windows, eating well when you eat, and treating the clock as a guide rather than a streak.
How to make fasting easier · Longer fasts · 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