# 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. Canonical: https://lucernel.com/guides/food-and-symptom-diary Last updated: 2026-09-30 Type: Guide. Publisher: Lucernel. ## 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. ## Side by side | | Notebook | Gutli | | --- | --- | --- | | Meals with time and portion | Yes, by hand | Yes, with gram quantities | | Symptoms with intensity | Yes | Yes, pain, bloating, nausea and energy | | Bristol stool chart | Partly, if you know the types | Yes, built in | | Meals and symptoms on one timeline | No | Yes, with a calendar | | Report for your dietitian | No, you bring the notebook | Yes, PDF and CSV | | Private | Yes | Yes, on 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. Disclosure: Gutli is made by Lucernel, the publisher of this article. ## 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](https://lucernel.com/apps/gutli) ## Sources (checked 2026-09-26) - [NIDDK: Eating, diet and nutrition for irritable bowel syndrome](https://www.niddk.nih.gov/health-information/digestive-diseases/irritable-bowel-syndrome/eating-diet-nutrition) - [Monash FODMAP: Practical tips for FODMAP reintroduction](https://www.monashfodmap.com/blog/practical-tips-fodmap-reintroduction/) - [Lewis SJ, Heaton KW. Stool form scale as a useful guide to intestinal transit time, 1997](https://pubmed.ncbi.nlm.nih.gov/9299672/)