Using before- and after-meal readings to find meals that suit you

An after-meal number on its own doesn't tell you whether you started high or whether the meal pushed you up. Checking before and after as a pair shows the meal's effect.

How to check in pairs

1. Check your before-meal blood sugar right before you eat.
2. Note what you ate and roughly how much.
3. Check again 1 or 2 hours after your first bite — the same time point each time.
4. Subtract the before-meal value from the after-meal value to see how much that meal raised you.

What to compare

• Compare days with the same meal. Different portions or sides change the result.
• Note what you changed — portion size, eating vegetables first, a walk after eating — so you can see what helped.
• Don't draw conclusions from one or two tries; repeat and compare.

How big a rise is OK?

The rise varies by person and by food, so there is no single right answer. Follow your care team's after-meal target, and use the difference to compare which meals are harder on you.

This article is general health information and does not replace diagnosis or treatment. Targets and how often to check differ from person to person, so follow your care team first. If you have symptoms of low blood sugar or readings far outside your range, contact your care team right away.

Reference: American Diabetes Association (ADA) Standards of Care

Last updated 2026-10-26