High Blood Sugar Even When You Eat Well

High blood sugar despite eating carefully is one of the most demoralising things in diabetes, and it usually means the cause is not on your plate.

Things that raise readings without any food involved

• Short sleep. A systematic review found that even a single night of partial sleep deprivation measurably increased insulin resistance. Restricting sleep to 6.5 hours raised fasting glucose by around 8% and post-meal glucose by around 14%.
• Stress. Stress hormones raise glucose directly, which is why a difficult month shows in the numbers.
• Illness. A fever or infection pushes readings up even when you are eating less than usual.
• Medicines. Steroids are the clearest example, and they can raise blood sugar sharply.
• Body clock disruption. Shift work and very late meals raise post-meal glucose even when the food is identical.
• The dawn phenomenon, which raises morning readings before you have eaten anything.

Portion creep is the one dietary cause worth checking, because it is invisible. Roti sizes grow, the katori of rice becomes a heaped one, and nothing about the meal has changed except its quantity.

The practical move is to stop adjusting your diet in the dark. Write down what else was happening — sleep, stress, illness, a new medicine — beside a week of readings, and the pattern usually names itself. If it does not, that is a reason to review treatment rather than to eat less.