What Happens to Your Blood Sugar When You Eat White Bread Every Day

White bread is a staple in many American households. While it’s delicious, experts say it’s not the healthiest choice, and eating it regularly can have a negative effect on your blood sugar.

Why White Bread Spikes Blood Sugar

White bread, which is processed and made with just the starchy endosperm of a grain kernel, has a high glycemic index of around 70-75, said Matthew J. Landry, PhD, RDN, an assistant professor of population health and disease prevention at UC Irvine Joe C. Wen School of Population & Public Health.

“This means that it’s rapidly digested and absorbed by the body. In the short term, this can cause blood glucose, aka blood sugar, to rise quickly within 15-30 minutes of consumption, followed by a relatively sharp decline as insulin responds,” Landry said.

He added that eating high-glycemic foods like white bread regularly can increase insulin demand, which may raise the risk of insulin resistance over time.

It Lacks Fiber

When wheat is processed to make white flour, the bran—the high fiber portion—is removed. This makes white bread more quickly digested in the body, and it can cause a faster and higher spike in blood sugar as compared to whole grains, said Mindy Haar, PhD, RDN, assistant dean at New York Institute of Technology’s School of Health Professions.

“The more chemically complex the carbohydrate, the slower the breakdown process, and the more even the absorption of glucose into the blood,” Haar said.

Pairing White Bread With Other Foods Can Blunt Blood Sugar Spikes

The extent of the impact will vary. Landry said it all depends on someone’s metabolic health, what else is consumed with the bread, and the portion size of bread.

“Context really matters here since this is only one aspect of the entire diet,” he said. “If you pair white bread with protein, healthy fats, or fiber, then it can help negate some of the impacts on blood glucose levels.”

Whole Grain Bread Is Better for Blood Sugar Control

A better option for blood sugar balance would be whole grain bread.

“This is a better option because whole grains have all three parts of the grain kernel: the fiber-rich bran, the nutrient-dense germ, and the starchy endosperm,” Landry said. “Having all three rather than just the starchy endosperm that we find in white bread helps slow digestion and glucose absorption, resulting in a more gradual, sustained blood sugar rise rather than a spike.”

The bran layer in whole grain flour contains undigestible fiber that lengthens the digestive process and also acts as a “broom,” removing waste products from the body, Haar said.

Because whole grain products take longer to digest, you’ll also feel full for a longer period of time despite equal amounts of calorie consumption.

How to Choose a Blood Sugar–Friendly Bread

When shopping, don’t just look for a “whole grains” label on the packaging, since only a small amount of whole grains may actually be used to achieve this, Haar noted.

Instead, she suggests checking the actual Nutrition Facts label and confirming that one slice provides at least 3 grams of fiber. In comparison, white bread typically has 0, or at most, 0.5 grams.

Landry also recommends reading the ingredient list to ensure it says “whole” in the name of the ingredients, such as whole wheat flour. If it says “wheat flour” or “enriched flour,” then it’s refined, he said.