The two-week gut journal method.

The single most useful thing you can bring to a GP appointment about bloating, IBS or food intolerance is two honest weeks of notes. Here's how to keep them so the patterns actually show — on paper, in Notes, or in Glean.

Why two weeks, not three days

One rough evening tells you almost nothing — the same meal can sit fine on Tuesday and terribly on Friday, because sleep, stress, your cycle and how the food was cooked all move the needle. Patterns only separate from coincidence when they repeat.

Two weeks is the honest minimum: enough repeats of your usual meals to see whether a suspect keeps showing up, and short enough that you'll actually finish. Don't change how you eat during it — the point is to observe your normal life, not to run a diet.

What to write down (and what to skip)

• Every ingredient you can name — especially sauces, oils and seasonings. The trigger is more often in the dressing than the salad: onion or garlic in a sauce, a cream base, a shop-bought marinade.
• How it was cooked. Raw, fried, roasted or fermented versions of the same food can behave differently in the gut — raw vegetables and legumes ferment more than well-cooked ones; fried and very fatty meals sit longer.
• Homemade or packaged? A supermarket sliced loaf and a bakery sourdough are different foods to your gut — packaged versions often carry emulsifiers and preservatives some people notice.
• How you felt, with a time. Bloating, cramps, energy dips, how the loo went — a word or two and when. Timing matters: reactions to dairy often appear within 1–4 hours, fermentable-carb (FODMAP) reactions typically 4–8 hours, so the culprit is often an earlier meal than you'd guess.
• The context. Poor night's sleep, stressful day, where you are in your cycle, feeling unwell — these can imitate food reactions, and noting them stops false accusations.
• Skip the numbers. No calories, no scores. Rough amounts are plenty ("two eggs", "a big bowl") — precision only really matters later, if you're re-introducing a food and want to know whether a little of it sits differently to a lot.

How to read it back

At the end of each week, read the fortnight so far with three questions:

• What repeats? A food that's followed by the same complaint three or four times is a lead. Once is nothing.
• What else was true those days? If the "bread bloating" only happens on four-hours-of-sleep days, sleep is a suspect too.
• What's normal for you? Judge changes against your own baseline, not a textbook. If you're usually constipated, a food that's followed by finally going comfortably is a good sign, not a bad one.

Group look-alike foods when you read: onion, garlic and leek behave as a family (the alliums); milk, cream and soft cheese carry the same lactose load. A pattern that's invisible meal-by-meal often appears family-by-family.

Taking it to your GP

Bring the diary, not a conclusion. "Bloating followed onion-heavy meals on four of five occasions, usually within the evening" is something a GP can work with; "I think I'm intolerant to everything" isn't. Ask what they'd want ruled out first — keeping a food and symptom diary is exactly what NHS guidance suggests before trying exclusion diets, and coeliac testing needs you to still be eating gluten, which is another reason not to cut things out on your own.

Or let Glean keep it for you

Glean is this method as an app: log a meal by typing, speaking or photographing it, note how you feel in a couple of taps, and it reads the fortnight for you — grouping the food families, weighing the timing windows, setting aside the poorly-slept days — then writes it up plainly. Free to try, on the App Store.

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