You May Be Buying Fake Sourdough Bread: Here's How to Tell

It seems like everyone is baking sourdough bread these days. Aside from tasting great, it is also deemed healthier compared to regular white bread.

The science actually backs this up (with a few caveats). Authentic sourdough uses a live culture (called a starter) and ferments for 12-24 hours. During that time, bacteria produce acids that slow down how fast your body digests the carbs. As a result, it has less of an impact on your blood sugar response after eating it.

This is not just theory, it is supported by research. A study by Liljeberg et al. showed that adding lactic acid, the acid produced from the bacteria, lowered blood glucose and insulin responses in healthy adults.

The problem for consumers is that "sourdough" is not a regulated term. A loaf of sourdough bread you see on a grocery store shelf may not have the fermentation benefits that it should. That 12-24 hour fermentation is what provides the health benefits. A loaf can just have "sourdough flavoring" with the word sourdough slapped on the label.

According to scientist William Wallace, if you see the words yeast, vinegar, acetic acid, or natural flavor on the label, it was not fermented in the traditional sense. It may provide some benefit, but it's certainly not what you're looking for.

The health benefits of sourdough are real, but they live in the process, not the packaging. To actually get those benefits, check the label for flour, water, salt, and starter; that's it. Better yet, seek out a local bakery that uses a traditional starter and a long ferment, or make it yourself. Your blood sugar will thank you.

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This story was originally published May 26, 2026 at 4:08 PM.