What Happens to Your Blood Sugar When You Eat Sourdough Bread Regularly

Posted by AweSamo December 16, 2025
What Happens to Your Blood Sugar When You Eat Sourdough Bread Regularly

Key Takeaways

  • Sourdough bread has a lower glycemic index than regular white or yeast-leavened bread, resulting in a slightly less drastic rise in blood sugar after consumption.
  • The fermentation process used to make sourdough affects its nutritional value and digestibility, which in turn supports gut health.
  • Choosing authentic, whole-grain sourdough and pairing it with protein or healthy fats offers the best benefits for blood sugar balance and overall wellness.

Sourdough bread may have a less significant impact on your blood sugar levels than standard loaves of bread due to the fermentation process involved in making sourdough.

Sourdough Helps Stabilize Blood Sugar

Sourdough bread can help stabilize blood sugar to an extent. If you’re an avid sourdough fan, you might reap some blood sugar benefits from choosing it over other types of more quickly digested breads.

The organic acids formed during the fermentation of sourdough slow the rate at which carbohydrates are digested and absorbed, potentially leading to a more gradual rise in blood glucose (sugar) and insulin, the hormone released to lower blood sugar levels after meals.

The Science of Sourdough and Blood Sugar

Some studies have shown that regular consumption of fermented foods can modestly improve blood sugar control, insulin sensitivity, and even heart health risk factors in people with diabetes or prediabetes.

One recent review and meta-analysis of 18 clinical trials compared the effects of sourdough with industrially fermented breads or sugar solutions on blood sugar and appetite-regulating hormones in adults.

The researchers found that eating sourdough bread led to much smaller increases in blood glucose both 60 minutes and 120 minutes after eating, compared to other breads or the sugar solution.

These results suggest that sourdough causes a lower post-meal blood sugar spike, especially when it’s made with whole wheat flour. However, eating sourdough did not lower fasting insulin or have a beneficial effect on appetite hormones.

Although the evidence quality was rated as low to very low, the findings suggest that consuming sourdough bread may help reduce blood sugar spikes after eating it.

What Makes Sourdough Unique

The process of making sourdough bread is a slower method that incorporates fermentation, allowing the microbes to partially break down the starches and gluten in the flour. This process changes the bread’s texture, flavor, and nutritional profile.

Sourdough bread often has a lower glycemic index (GI) than conventionally made bread, meaning it’s less likely to cause sharp blood sugar spikes after eating. The GI is a measure that scores foods on a scale of 1-100 based on how they affect blood sugar (the higher the GI, the more dramatic the spike).

Tips to Reduce Blood Sugar Spikes When Eating Bread

Many people enjoy the flavor of sourdough bread and its health benefits, including a gentler effect on blood sugar compared to other types of bread. If you’re looking to get a better handle on your blood sugar control, here are some ways you can do that while enjoying sourdough:

  • Choose whole-grain sourdough varieties, which have more fiber and are more slowly digested than white or refined breads.
  • Pair your bread with protein and healthy fats, such as avocado, peanut butter, or hummus, to further help reduce blood sugar spikes.
  • Monitor your portion sizes, as even healthier breads can increase blood sugar if eaten in excess.

Combining these strategies helps you enjoy sourdough bread while maintaining smoother, more stable energy throughout the day.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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  2. Zhang XF, Qi Y, Zhang YP, et al. Fermented foods and metabolic outcomes in diabetes and prediabetes: A systematic review and meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr. 2024;64(26):9514-9531. doi:10.1080/10408398.2023.2213770

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  6. Rolim ME, Fortes MI, Von Frankenberg A, et al. Consumption of sourdough bread and changes in the glycemic control and satiety: A systematic review. Crit Rev Food Sci Nutr. 2024;64(3):801-816. doi:10.1080/10408398.2022.2108756

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By Lauren Panoff, MPH, RD

Panoff is a registered dietitian, writer, and speaker with over a decade of experience specializing in the health benefits of a plant-based lifestyle.

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