If your facility has given you a cut-off time, that's the one you must follow, and this page is only meant to help you understand it. If you haven't received anything, or if the instructions aren't clear, call the department: the fasting time depends on the actual time of the anesthesia, which you don't yet know.
The following shows how these hours are calculated in the published recommendations, and where each figure comes from. This is an illustration, not a personal instruction.
Last meal at the latest ….
Last glass of water at the latest ….
| What we swallow | At the latest | Recommended deadline | Source |
|---|---|---|---|
| Fatty, fried, or meaty meals A dish with sauce, a fried dish, a meat dish. |
... | 8 hours or moreAdditional fasting time (e.g., 8 or more hours) may be needed | American Society of Anesthesiologists |
| Light meal Defined by the source as toast and clear liquids. |
... | 6 hoursLight meal: 6 hours | American Society of Anesthesiologists |
| Cow's milk, plant-based milk, infant formula Milk behaves like a solid in the stomach. |
... | 6 hoursInfant formula: 6 hours / Nonhuman milk: 6 hours | American Society of Anesthesiologists |
| Breastmilk The only point where the two sources do not say the same thing after 6 months. |
... | 4 hoursBreast milk: 4 hoursFrench Hospital Federation: 4 hours before 6 months, 6 hours after 6 months. | American Society of Anesthesiologists et French Hospital Federation |
| Clear liquids Allowed: water, tea or coffee without milk, filtered juice. To avoid: milk, alcohol, and any juice containing pulp. |
... | 2 hoursClear liquids: 2 hours | American Society of Anesthesiologists |
Your anesthesia team's instructions always take precedence over this tool. If the hospital has given you a specific time, follow theirs, even if it differs from this chart. Protocols vary from one facility to another, and your anesthesiologist may have information not included on this page.
Why does the time of the last meal often fall the day before?
This is the calculation no one does in their head at 23 p.m. For a procedure at 8 a.m., a light meal should be finished by 2 a.m., which in practice means the night before. A fatty or meaty meal should be eaten by midnight the night before. The limit for clear liquids, however, falls much later in the morning according to these same recommendations.
One point worth noting, provided you confirm it with your team: the American Society of Anesthesiologists recommendation cited here, like the French guidelines, sets the limit for clear liquids at two hours. Many people stop drinking much earlier without being asked. If this is the case for you, ask rather than deciding on your own, as some protocols and situations require a longer limit.
What this tool does not cover
The recommendations reproduced here apply, according to their own text, to healthy patients and scheduled interventions. The source explicitly excludes women in labor and indicates that the durations may need to be modified in several situations:
- Pregnancy, obesity, diabetes, hiatal hernia, gastroesophageal reflux, and more broadly any known disorder of gastric emptying
- Intestinal obstruction or ileus, tube feeding, and any situation where the team anticipates difficult airways
- labor and childbirth, which the cited document explicitly excludes from its scope
- emergency surgery, where the calculation does not apply
- treatments that slow down digestion, including some recent medications for diabetes and overweight
In all these cases, only your team can set the time. And the source itself says so: « following the guidelines does not guarantee complete gastric emptying »Meeting deadlines does not guarantee an empty stomach.
Where do the figures come from?
Two documents, both public and linked in the table. The main durations come from the American Society of Anesthesiologists' recommendations on preoperative fasting. The pediatric durations are compared to the French Hospital Federation's guidelines, which use the same framework with one difference: it groups all milks by age, four hours before six months and six hours after, whereas the American source distinguishes between breast milk (four hours at any age) and infant formula (six hours).
When two sources diverge, this tool uses the longer timeframe. This is the prudent choice, and it is indicated in the table.
The same work, applied to the post-operation period, can be found in our reference guide for recovery times : 90 recommendations gathered from twelve health institutions, each with its original citation.
This page is not a substitute for medical advice. It presents public recommendations and has no knowledge of your medical history. If you have eaten or drunk anything after the cut-off time, inform the team before the procedure, without exception and without waiting to be asked. They will decide whether the procedure can proceed, be modified, or postponed. Remaining silent is the only truly dangerous option.
