Do not delete the days you travel from a food and symptom diary. Keep them, label them as travel or changed-routine days, write real clock times, mark the meals you could not identify, and compare them with other travel days rather than with your usual week. A travel day is unusual in many ways at once, so it cannot show which single change mattered. It can still be an honest part of the record.
This guide is about how to record. It does not say what you should eat while away, and it cannot tell you why your digestion felt different on a trip.
Why travel days are hard to read
On a trip, meals, sleep, activity, drinks, toilets and stress can all change together. If symptoms change as well, a diary cannot separate those threads. That is a reason to label the days clearly, not a reason to remove them.
There is some evidence that travel is linked with digestive change, though it is limited. A retrospective study of travel-clinic patients at the University of Utah, mostly returned missionaries, reported that many people with no symptoms before travel developed new diarrhoea, bloating, constipation or indigestion during travel, and that these often continued after they returned. It was retrospective and drew on one clinic’s patients, so it cannot tell you how common this is, and only its abstract is openly readable. The NHS describes jet lag as something that can sometimes bring indigestion, nausea, constipation and changes in appetite, usually improving within a few days.
Neither source says what will happen to you, or which part of a trip is responsible. They do suggest why it helps to keep the days rather than throw them out.
Label the kind of day
Add one short label beside the date. Keep the set small:
- Travel day (in transit).
- Away, settled (staying somewhere, routine still different).
- Changed routine at home (visitors, time off, a disrupted week).
- Back to usual.
A label describes the day. It does not say the trip did anything. It lets you later look at “settled days away” together and ask whether they resemble each other, as the guide to selecting context suggests for any context you add.
Use clock times, and say which clock
After a time-zone change, “morning” and “evening” can mean different things on the same day. Write the date and a 24-hour time for each meal, drink and symptom, and put the time zone at the top of the day, for example “local time, UTC+2” or “still on home time”. If you changed your phone clock part-way through, note it. The shift-work diary guide explains the same idea for irregular meals.
Recording sleep as start and end times is usually enough to show how far the day has shifted; the guide to recording sleep covers this without reading too much into it. Research summaries describe jet lag as a period when sleep, waking and meals fall at times that do not match the body clock, but no trial evidence was found that any particular meal timing changes digestive symptoms, so treat the clocks as a record, not a remedy.
Record uncertain meals plainly
Away from home you may not know what is in a dish, how large the portion was, or how it was cooked. Write what you can see and what you cannot:
- “Local fish stew, ate about half, ingredients unknown.”
- “Hotel buffet, small plate of bread, eggs and fruit, not sure what was in the sauce.”
- “Snacks from the airport shop, two items, ate over three hours.”
“Unknown” is a valid entry. It is more useful than a confident guess that you later treat as fact. The mixed-meal guide and guide to snacks and grazing describe how to keep this quick. Also note drinks and any change in what you drank, as in the drinks guide.
Note what changed, in a few words
Use a single context line rather than a log of everything: “long flight, mostly sitting”, “much more walking than usual”, “less sleep”, “unfamiliar water supply”, “no easy access to a toilet”. Pick only what you actually noticed. This stays context; do not add “because of” to the line.
Mark gaps and entries added later
Travel often interrupts recording. Write “no entries 08:00–20:00, travelling”, or mark an entry as “added afterwards” when you wrote it later from memory. The missing check-ins guide explains how unmarked gaps can make a record look more complete than it was.
Compare travel days with travel days
When you read the diary back, avoid lining up a travel day against a usual weekday and concluding that something on the plate made the difference. Look first at:
- travel days with other travel days;
- settled days away with each other;
- the days after you return, kept separate from the days before you left.
If the same sequence appears on several comparable days, it is a candidate to look at again; one trip is one sample. If it does not, that can still be a useful result. The timing and attribution guide explains why a single meal before a single symptom is not an answer.
When symptoms need medical advice
A diary is for recording, not for deciding whether symptoms are serious. TravelHealthPro, the UK travel health service, describes travellers’ diarrhoea as three or more unformed stools in 24 hours, usually starting during travel or within about 10 days of returning, often settling within three to four days. It advises seeking medical care if symptoms have not improved within three days, and urgent care for a fever of 38°C or more, blood or mucus in the stool, severe abdominal pain, confusion, jaundice or a rash. Its guidance on dehydration is that young children, older travellers and others at higher risk should seek early advice. The NHS diarrhoea guidance says to call 111 for bloody diarrhoea, diarrhoea lasting more than seven days, or being unable to keep fluids down, and to call 999 or go to A&E for vomiting blood, a sudden severe tummy ache or confusion.
If you are abroad, follow local emergency advice. If symptoms continue after you return, or you are worried, speak to your GP, and take the diary with you. The GP summary guide shows how to condense it. Do not cut out foods because of one trip; if you are considering a restrictive diet, discuss it with a doctor or dietitian first.
If a quick way to log meals and symptoms on the move would help, you can get GutBloom on Google Play.
Sources
- Tuteja et al., Digestive Diseases and Sciences (2008) — Development of functional diarrhea, constipation, irritable bowel syndrome, and dyspepsia during and after traveling outside the USA (abstract)
- TravelHealthPro (UK) — Travellers’ diarrhoea factsheet, updated 27 February 2024
- NHS — Jet lag
- NHS — Diarrhoea