Blood Sugar Log

Five columns

Date, time, before meal, after meal, notes. Twenty rows as standard, with a name and week-of line above them.

The unit is yours to set. Britain and Ireland use mmol/L, as does most of Europe; the United States and a number of other countries use mg/dL, and the column headers change accordingly so nobody is left converting in their head.

Before and after are different questions

The two columns are separate because they measure separate things.

A before-meal reading tells you where your baseline sits. An after-meal reading — usually taken about two hours later — tells you how a particular meal behaved. A person can have acceptable fasting numbers and large post-meal spikes, and vice versa, and only the pair together shows it.

Write down the time as well as the reading. "After lunch" and "two hours after lunch" are different measurements and only one of them is comparable with yesterday's.

The notes column is the useful one

Record what you ate, whether you exercised, how you slept, whether you were unwell, and any change to medication.

A reading on its own is a number. A reading with "large pasta lunch" beside it is an explanation, and the explanation is what lets you or your clinician change something. Illness moves glucose. So does stress, so does a bad night's sleep, all independently of what you ate — and without the notes those days simply read as unexplained bad results.

Patterns, not individual readings

One high reading means very little. The same reading at the same time of day, five days running, means a great deal.

Read the sheet in columns rather than rows — look down the before-breakfast entries for the week, then down the after-dinner ones. That is where a pattern lives, and it is why a full sheet is worth more to a clinician than a handful of remembered numbers.

Taking it to an appointment

Bring all of it, including the readings you were not pleased with. A log edited to look tidy leads to advice based on a fiction.

Many meters download to an app, which is more complete than this. It is also less legible in a ten-minute consultation, and it does not carry your notes about what you were eating.

Important

This sheet records; it does not interpret. Never change an insulin dose, a medication, or your diet on the strength of what you see here without talking to your diabetes team first.

Learn your own warning signs and act on them rather than on the log. If you have symptoms of a hypo, treat it immediately; if readings are persistently very high, or you are unwell and ketones are present, contact your healthcare provider straight away.