Fix the mistake, but leave the first version readable. Cross out or mark the old wording rather than deleting it, write the corrected version beside it, and add the date you made the change and, if it is not obvious, a few words on why. That way you can still see later what you originally wrote, what you changed it to, and when.
This guide explains why professional health and research records work this way, then shows a light version you can use in a paper notebook, a notes app or a spreadsheet. It is about keeping your own record honest. It does not tell you what any pattern in your diary means, and a personal diary is not bound by the rules described below.
Why not simply overwrite the mistake?
A diary is only useful for finding patterns if you can trust how it was made. Overwriting hides a change, and a hidden change is hard to account for later, even for you.
Official guidance for professional records is consistent on this point, although it was written for a different purpose:
- Health records. NHS England’s guidance on amending patient and service user records says that when staff correct an inaccurate entry, the original must not be deleted and must still be readable. For handwritten records it describes putting a single line through the error, initialling it and adding the correct information. For electronic systems it says an audit trail logs what was added or changed and when, and that a change made retrospectively should have a full explanation. The page was updated in May 2026 and is written for professionals who keep records, not for people keeping a personal diary.
- Clinical research. The international good clinical practice guideline, ICH E6(R3), adopted in January 2025, says source records should be attributable, legible, contemporaneous (made at the time), original, accurate and complete. It adds that changes should be traceable, should not obscure the original entry and should be explained if necessary. It applies to clinical trials.
- Regulated records more widely. The UK medicines regulator’s GXP data integrity guidance (March 2018) describes an audit trail that records the “who, what, when and why” of a change in paper or electronic records, without obscuring or overwriting the original. It covers regulated medicines and clinical-research settings.
These are standards for organisations whose records may be checked by others. None of them is a rule for your own notebook, and none of them is evidence that corrected diaries produce better conclusions. They are useful because they show what a long-established answer to the same problem looks like: keep the original, make the change visible, say when, and say why if it is not obvious.
What counts as a correction?
It helps to separate three things people often mix together.
- A mistake of fact. You wrote “wholemeal toast” but it was a seeded bagel, or you wrote 7:30 for a meal you had at 8:30. This is a correction.
- A detail you forgot. You remember later that there was a drink with the meal. This is an addition. You are not changing what you wrote, only adding to it, so mark it as added later.
- A change of mind about what it means. You now suspect the onions, or that the evening symptom was “really” from lunch. This is not a correction at all. It is an interpretation, and it belongs in a separate note, not in the entry itself.
Keeping the third kind out of the entry matters. If you rewrite what happened to fit a theory, the diary can no longer test the theory, because the record has been shaped by it. This is a practical point about how the record is built, not a finding from a study.
A light way to do it
Pick the version that matches your tool and use it the same way each time.
On paper
- Draw one line through the wrong wording so that it can still be read.
- Write the corrected wording beside it.
- Add the date you made the change, for example “corrected 16 Oct”.
- If the reason is not obvious, add a few words, such as “wrong bread” or “checked the receipt”.
Avoid correction fluid, scribbling out and tearing pages. The aim is that anyone looking at the page, including you in a month, can read both versions.
In a notes app
Leave the original line in place and add a line directly under it:
Correction (added 16 Oct): bagel, not toast. Checked the packaging.
If you prefer to edit in place, copy the original wording into a note first, so that it survives the edit.
In a spreadsheet
Do not type over the cell. Add columns, such as “Changed to”, “Changed on” and “Reason”, and leave the original cell as it was. The downloadable diary template is a plain table, so you can add these columns yourself if you want them.
In a diary app
Check whether the app keeps a history of edits or simply replaces the old value. Some tools keep one and others simply replace the old value. If yours replaces it, add a short note in the entry saying what changed, for example “time changed from 13:00 to 14:00 after checking my messages”. If you are not sure how your tool behaves, assume it does not keep a history.
Mark the entries you only added later
Corrections and late additions both depend on when you made them. The article on whether it matters if you write an entry at the time or afterwards describes simple markers such as “live”, “later today” and “estimated”. A correction made a week later from a receipt is more reliable than one made from memory, and a short phrase like “checked the receipt” or “from memory” records that difference in a few words.
If the problem is a gap rather than a mistake, the guide to missing symptom check-ins covers why an empty stretch should not be treated as a symptom-free one.
Using corrected entries when you review
When you look back over several days, use the corrected wording, since that is your best account. Keep the original visible so you can see how often you changed things and which kinds of entries needed it.
- If most of your corrections concern portion size or time, that is a hint that those details are less reliable in your diary than the rest. Treat comparisons that depend on them with extra caution.
- If you change the same kind of entry again and again, try noting it more simply at the time. The guide to recording a mixed meal describes a manageable level of detail.
- Do not change an entry because it does not fit what you expected to see. A record that has been tidied to match a pattern cannot show that the pattern was real. The article on what it means when a food diary shows no clear pattern explains why an unclear result is still a result.
A visible correction does not make a record accurate. It makes the record honest about its own history, which is a lower bar and a more achievable one.
If you share the diary with a doctor or dietitian
You do not need to tidy it first. A short remark such as “I corrected a few times; the original wording is still readable” is enough. If a clinic or dietitian has given you their own diary form, follow their instructions for filling it in, since they may want it done in a particular way. The guide to what to bring to a dietitian appointment covers preparing the record for that conversation.
GutBloom is designed to reduce the effort of recording while keeping your corrections and uncertainty visible. If that would suit the way you keep a record, you can get GutBloom on Google Play.
When to speak to a professional
Do not wait for a perfect diary before asking for help. The NHS bloating page advises seeing a GP if you feel bloated regularly, still feel bloated after changing your diet, or have bloating with unintentional weight loss or blood in your poo. It advises getting urgent help for bloating with vomiting, diarrhoea or constipation, a stomach ache, a high temperature, a swelling or lump in your tummy, an inability to pass wind or stools, or acid reflux, and calling 999 or going to A&E for a swollen stomach with a sudden severe stomach ache, vomiting blood or severe breathing difficulty. The page was last reviewed on 21 January 2026, so check the current version.
This article has not been professionally reviewed and is not medical advice.
Sources
- NHS England — Amending patient and service user records
- International Council for Harmonisation — ICH E6(R3) Good Clinical Practice, final version adopted 6 January 2025
- Medicines and Healthcare products Regulatory Agency — ‘GXP’ Data Integrity Guidance and Definitions, Revision 1, March 2018
- NHS — Bloating