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How to keep a food and symptom diary your dietitian can use

What to write down in a food and symptom diary for IBS or the low-FODMAP diet, how long to keep it, and how to make it useful for your doctor or dietitian.

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On this page
  1. 1Short answer
  2. 2At a glance
  3. 3Why keep a diary
  4. 4What to write down
  5. 5How long and how often
  6. 6Making it useful for your clinician
  7. 7FAQ
  8. 8Our pick

Short answer

A useful food and symptom diary records what you ate, how much and when, then your symptoms with their time and intensity, your bowel movements on the Bristol scale, and context such as sleep and stress. Keep it every day for at least two weeks, on good days too, and bring it to your doctor or dietitian.

Choose this if

A notebook works if you write everything down right after each meal.

Choose the other option if

Gutli helps when you want meals, symptoms and the Bristol type on one timeline and a report ready for your dietitian.

At a glance

FeatureNotebookGutli
Meals with time and portionYesby handYeswith gram quantities
Symptoms with intensityYesYespain, bloating, nausea and energy
Bristol stool chartPartlyif you know the typesYesbuilt in
Meals and symptoms on one timelineNoYeswith a calendar
Report for your dietitianNoyou bring the notebookYesPDF and CSV
PrivateYesYeson your iPhone only

Why keep a diary

IBS symptoms can come hours after a meal and depend on the amount eaten, so memory is a poor guide. A diary turns guesses into a record that you and your clinician can read, and it is the backbone of the reintroduction phase of the low-FODMAP diet.

The US National Institute of Diabetes and Digestive and Kidney Diseases notes that you may need to change what you eat for several weeks to see whether symptoms improve, and that a dietitian can help. A diary shows whether a change worked.

What to write down

  • Every meal, snack and drink, with the time and an honest portion size.
  • Symptoms such as pain, bloating, gas, nausea and urgency, with the time they started and how strong they were on a 0 to 10 scale.
  • Bowel movements, with the type from the Bristol stool chart.
  • Context that changes digestion: sleep, stress, exercise, alcohol, medication and your period.
  • Good days too: without them, you cannot compare.

How long and how often

Write things down right after they happen; filling in the evening before bed loses details. Two weeks is a reasonable first stretch before a doctor’s visit, and the whole low-FODMAP process, from elimination through reintroduction, usually takes longer.

During reintroduction, test one FODMAP group at a time over three days and note the portion that caused symptoms, if any.

Making it useful for your clinician

Clinicians read quickly. A summary per week, symptom days highlighted, and the Bristol types over time help more than pages of notes. Bring the raw diary too, in case they want to check a detail.

A diary shows patterns, not causes. A food that appears before bad days is a lead to test, not a verdict, and new or severe symptoms such as blood in the stool or weight loss you cannot explain need a doctor right away.

Frequently asked questions

What should I record in a food diary for IBS?

Meals and drinks with time and portion, symptoms with time and intensity, bowel movements on the Bristol scale, and context such as sleep, stress and medication.

How long should I keep a food and symptom diary?

At least two weeks before drawing conclusions, and through the whole reintroduction phase if you follow the low-FODMAP diet.

Should I log days without symptoms?

Yes. Good days are what you compare bad days with; without them, patterns are invisible.

Can a diary tell me which foods trigger my symptoms?

It shows patterns to test. A structured reintroduction, ideally with a dietitian, tells you which FODMAP groups you tolerate.

Is Gutli available?

See the official app page for current availability and pricing.

Our pick

Gutli, a food and symptom journal for low-FODMAP

Gutli records meals with portions, symptoms, bowel check-ins with the Bristol chart and each reintroduction challenge on one timeline, then turns them into a report your dietitian can read.

  • Meals with portions and an optional photo
  • Symptoms and the Bristol chart
  • PDF and CSV reports for your clinician
See how Gutli works

Sources · checked September 26, 2026

  1. NIDDK: Eating, diet and nutrition for irritable bowel syndrome
  2. Monash FODMAP: Practical tips for FODMAP reintroduction
  3. Lewis SJ, Heaton KW. Stool form scale as a useful guide to intestinal transit time, 1997