How to keep a food and symptom diary for IBS
“I think dairy bothers me, maybe?” is hard to act on. Three weeks of dated meals and symptoms is not. A good food and symptom diary turns guesses into patterns you and your clinician can actually test.
What to log
You do not need to weigh every gram. You need enough detail to compare days.
For every meal or snack
- The time you ate
- What you ate, including sauces, drinks and seasonings (garlic and onion hide in a lot of them)
- A rough portion: “a handful”, “half a plate”, “two slices”
For every symptom
- The time it started
- What it was: bloating, pain, gas, urgency, constipation, nausea
- How bad it was, on a 1 to 10 scale
Once a day, if you can
- Stool type (many clinicians use the Bristol Stool Scale)
- Sleep, stress and your menstrual cycle, which can all affect gut symptoms
How long to keep it
Aim for at least two weeks before you look for patterns, and bring the full record to your appointment. One bad day after pizza proves little. Five bad days after meals with onion start to mean something.
How to read the patterns
- Look at timing, not only the last meal. Symptoms can show up shortly after eating or many hours later, so the culprit is not always the most recent thing you ate.
- Look for repeats. A food that shows up before most of your worst days is worth testing.
- Remember dose. A small amount may be fine while a large serving is not.
- Treat patterns as questions, not answers. A pattern is a timing coincidence until you test it, ideally with a dietitian through the low FODMAP reintroduction phase.
Paper, notes app or a dedicated tracker?
Any diary you actually keep beats a perfect one you abandon. Paper is simple but hard to search. A notes app is quick but makes patterns hard to spot.
A dedicated tracker like Fodia puts meals and symptoms on one timeline, lets you log a meal by typing it or snapping a photo, and summarizes the timing patterns in your own entries. Your diary is encrypted on your device, and you can export a clean CSV for your doctor whenever you need it.
Bring it to your appointment
Before your visit, note your three most frequent symptoms, the foods you suspect, and any questions. Your diary then gives your doctor or dietitian dated evidence instead of memories.