Whole grain bread or sourdough bread: which is better for blood sugar?

Some breads are better than others at preventing blood sugar spikes. However, it’s unclear whether whole grains are “better” than sourdough if you want better blood sugar management. Both have advantages. It may be best to opt for whole grain sourdough bread.

Both Types of Bread Have Blood Sugar Benefits

“Whole grains and sourdough describe two different things,” Meaghan Ormsby, MS, RDN, telehealth registered dietitian at Sound Nutrition Counseling, told Verywell. “‘Whole grain’ tells us about the grain or flour used, while ‘sourdough’ tells us about the fermentation process. They are therefore not necessarily opposed.

Both varieties have advantages. “Whole grain breads generally provide more fiber and retain more of the nutrients found in whole grains,” Ormsby said. “Fiber is important because it can slow the digestion and absorption of glucose, which is part of the reason why high-fiber breads can be a helpful option.”

Fermentation also matters. “The potential blood sugar benefit of sourdough comes largely from fermentation: organic acids produced during sourdough fermentation can slow starch digestion and contribute to a more gradual glucose response,” Ormsby said.

Other factors play a role in blood sugar response

Grain processing contributes to blood sugar spikes. “Bread with more intact or coarsely ground grains may affect blood sugar differently than bread made from very finely ground flour,” Ormsby said.

Portion size also affects blood sugar response. “The total amount of carbohydrate ingested is an important determinant of post-meal blood sugar response,” Ormsby said. “Two slices will generally provide more carbohydrates than one, whether the bread is sourdough or whole grain.”

Why whole grain sourdough is a good choice

A whole-grain sourdough combines the benefits of both: high fiber and fermentation, said Julia Zumpano, RD, a registered dietitian at the Cleveland Clinic. “Sourdough is made by fermenting flour and water using lactic acid bacteria and natural yeast, while whole grain bread uses commercial yeast.”

But there’s no “best” option if you’re trying to control your blood sugar. It might be worth looking beyond the specific type of bread you’re eating and analyzing your entire meal.

“As a dietitian who frequently works with insulin and glucose issues, one of the things I focus on most with my clients is what they eat with the bread,” Ormsby said. “We rarely eat bread alone, and pairing carbohydrates with protein and/or fats can help buffer the glucose response by slowing digestion and absorption. Think toast with eggs or peanut butter, a sandwich with protein, or bread with a meal rather than bread alone.”