Fasting and shift work
How to plan times around night shifts, early starts and rotating rosters, with worked examples.
Talk with a healthcare professional before changing how you eat if you have a medical condition, take medication, are pregnant or breastfeeding, are under 18, or have a history of disordered eating. Stop and seek help if you feel unwell.
Why shift work changes the maths
Most fasting advice assumes you sleep at night and eat during the day. Shift workers often eat across midnight, sleep in the daytime and change pattern between work days and days off. The tools here work with any clock times, including windows that cross midnight, so you can plan around your real day rather than someone else’s.
Anchor to your sleep, not the clock
An easy rule is to put the long gap around your main sleep. If you sleep from 08:00 to 15:00 after a night shift, the hours just before and during that sleep are a natural time not to eat, and your window can sit in your waking hours.
Worked examples
| Roster | Main sleep | Example window | Hours outside |
|---|---|---|---|
| Night shift 22:00–06:00 | 08:00–15:00 | 16:00–02:00 (10 h) | 14 |
| Evening shift 15:00–23:00 | 00:30–08:30 | 10:00–20:00 (10 h) | 14 |
| Early shift 06:00–14:00 | 21:30–05:00 | 06:00–18:00 (12 h) | 12 |
The night-shift window closes after midnight; the eating-window calculator labels this “closes the next day”.
Rotating shifts and changeover days
Switching from days to nights is already demanding. Many people find it easier not to aim for any particular fasting duration on changeover days and to eat when they need to. The weekly planner lets each day have its own start time, or no plan at all, so you can match your roster week by week.
Safety on shift
- Do not drive, operate machinery or do safety-critical work while feeling faint, shaky or unusually tired. Eat something and take a break.
- Keep a snack and water available on long shifts, whatever your plan.
- If you take medicines with food or for diabetes, ask your clinician how to time them around shifts.
- Sleep matters. If a plan is cutting into your sleep, change the plan.
Reviewed October 2026 by Lee Palmer · How we write our guides · Report an error