How Food Affects Blood Sugar

Blood sugar, also called blood glucose, is the sugar in your blood. Food changes it.

Carbs, short for carbohydrates, are the sugars and starches in food. They raise blood sugar more than any other part of a meal. Think of carbs as a fast delivery truck for sugar. You find them in bread, rice, pasta, potatoes, fruit, milk and beans.

A plate seen from above with a blood sugar meter beside it. When the plate is mostly carbs, bread covers most of the plate and the meter rises high. When the plate is balanced, bread takes one quarter next to vegetables and chicken, and the meter rises only a little.

Protein, fat and fiber can slow how fast blood sugar rises when eaten with carbs. Think of them as speed bumps that slow the climb. Fiber is a plant part your body cannot fully break down.

No single food is banned. Balance and portions matter most.

Two lines climb after a meal: carbs alone rise fast, while carbs with protein and fiber rise slower.

Some people check blood sugar after a meal. The American Diabetes Association, or ADA, suggests a goal for that check. After a meal, it is under 180 mg/dL (under 10.0 mmol/L). Check 1 to 2 hours after the meal starts.

This is a general goal, not an order. Your doctor sets your own target.

A horizontal scale marking under 70, 80 to 130 and under 180, with both units at each mark.

Key takeaways

• Carbs usually raise blood sugar the most.
• Protein, fat and fiber can help slow that rise.
• Balance and portions count more than any one perfect food.

Try it

At your next meal with bread, rice or pasta, add an egg, some fish or some vegetables. If you already check after meals, note the reading 1 to 2 hours after you start eating. Talk with your doctor or care team before changing meals or checks.