How long before surgery should I stop eating?
Last updated September 3, 2026.
The usual rule is 6 hours for food and 2 hours for clear fluids. NHS adult fasting guidance says do not eat for six hours before the anesthetic and keep clear fluids, such as water, squash without bits, or tea and coffee without milk, going until two hours before. Fasting exists because anesthesia switches off the reflexes that protect your airway; food in the stomach can be vomited and inhaled into the lungs, which is genuinely dangerous. Milk, milky coffee, and fizzy drinks count as food or are discouraged. Chewing gum, sucking sweets, and smoking are out on the day. The NHS also stresses that if your team told you to fast, that instruction includes light snacks and sweets, and that water is sometimes allowed but only if your team says so.
What to do
- Follow your hospital letter first: specific instructions from your team beat any general guideline.
- No food for 6 hours before anesthesia, including milk and snacks.
- Clear fluids until 2 hours: water, squash without bits, black tea or coffee.
- Skip gum, sweets, and smoking on the day of surgery.
- Be honest at check-in if you ate or drank inside the window; it changes the plan, not your worthiness for surgery.
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