Why Sourdough Is the Best

If you're going to eat bread, sourdough is the one I actually recommend. Not because it's trendy right now. Because of what happens to the dough before it ever hits your kitchen table.

Real sourdough is made with just flour, water, salt, and a wild yeast starter that's been fed and fermented for hours, sometimes days. That long, slow fermentation is what makes sourdough gentler on your blood sugar, easier on your gut, and a completely different food than the bagged, bleached-flour loaf sitting on a grocery store shelf. Here's the truth: not all bread is created equal, and sourdough is the one worth making room for.

Hi, I'm Sheri, Founder of Yonder & Certified Health Coach. I've spent over a decade studying metabolic health and clean nutrition, and bread is one of the most common places I see women unknowingly work against their own blood sugar. This is one of my favorite fixes: same bread aisle, completely different food.

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Store-bought bread is not just flour and water anymore

Walk down a bread aisle and read the ingredient list on most sandwich loaves. Bleached or bromated flour. Added sugar. Soybean or canola oil. Dough conditioners, preservatives, sometimes a dozen ingredients you'd never keep in your own kitchen. That's not bread. That's a manufactured product built to sit on a shelf for weeks.

Real sourdough has four ingredients. Flour, water, salt, and time. No seed oils. No dough conditioners. No added sugar to feed the yeast, because the wild yeast in the starter does that work on its own, slowly, the way bread has been made for thousands of years before industrial baking sped everything up.

Why sourdough is gentler on your blood sugar

This is the part that surprises people. Sourdough and a regular white sandwich loaf can have nearly identical flour, yet land very differently on your blood sugar.

According to PubMed, a randomized crossover trial comparing a sourdough rye bread meal to a conventional fast-food meal matched for calories found the sourdough rye meal produced a 44% lower rise in blood glucose and insulin after eating (Ramel et al., 2012, European Journal of Clinical Nutrition, DOI). That's not a small difference.

The mechanism comes down to fermentation. During sourdough's long rise, wild yeast and lactic acid bacteria produce organic acids that slow the rate at which your body breaks the bread's starch down into sugar. Research comparing sourdough-fermented rye and barley breads to conventional versions has repeatedly found lower glycemic and insulin index values in the fermented breads (Liljeberg & Björck, 1994, European Journal of Clinical Nutrition, PMID 8194500; Rosén et al., 2009, Nutrition Journal, DOI). A 2022 systematic review of 25 clinical trials on sourdough bread and health, covering 542 people, found sourdough was associated with improved glucose response, satiety, and gastrointestinal comfort compared to yeast-leavened bread in trials that used specific fermentation strains and conditions (Ribet et al., 2022, Advances in Nutrition, DOI).

Here's the part people miss. It's not the wheat that's the problem. It's how fast we've forced bread to be made. Slow it back down through real fermentation and the same flour behaves completely differently in your body.

Why sourdough is easier on your gut

Sourdough starters are alive. They carry over 60 different species of lactic acid bacteria, many of which overlap directly with the bacteria naturally found in the human gut (Gobbetti et al., 2016, International Journal of Food Microbiology, DOI). Some of those lactic acid bacteria strains are considered probiotic and have shown real potential for supporting gastrointestinal health (Lau et al., 2021, Microorganisms, DOI).

Fermentation also breaks down a meaningful portion of the gluten and gliadin proteins in wheat before you ever eat it. One study found sourdough fermentation with selected lactic acid bacteria degraded roughly 28% of the immune-reactive gluten in wheat flour while still producing a bread with good structure and taste (Rizzello et al., 2013, Food Microbiology, DOI). A more recent proteomic study confirmed that sourdough fermentation reduces specific allergenic wheat protein fractions through the organic acids the bacteria produce (Menezes et al., 2023, Food Chemistry, DOI). And in colonic fermentation research, fiber-enriched sourdough bread increased beneficial short-chain fatty acids like acetic and butyric acid while shifting gut bacteria populations in a favorable direction (Nieto et al., 2024, International Journal of Biological Macromolecules, DOI).

I am not going to tell you sourdough treats or cures anything. That's not how food works, and it's not how I talk about it. What I will tell you, plainly, is that a bread made through real fermentation is doing your gut a lot of favors that a fast-rise commercial loaf simply cannot.

Fermentation also unlocks more of the minerals in the flour

Whole grain flour naturally contains phytic acid, which binds to minerals like iron, zinc, and magnesium and makes them harder for your body to absorb. The long fermentation in sourdough activates enzymes that break down phytic acid, which increases the mineral bioavailability of the bread while also improving its texture and shelf life (Arendt et al., 2006, Food Microbiology, DOI). Same flour, more usable nutrition, simply because it was given the time to ferment properly.

The freeze-it, slice-it, toast-it trick

Here's a habit I use in my own kitchen every week. I slice a fresh sourdough loaf the day I bring it home, freeze the slices flat, and pull out only what I need. Then I toast it straight from frozen.

Toasting isn't just about texture. Bread that has cooled or been frozen goes through a process called starch retrogradation, where some of the starch reorganizes into a form your body digests more slowly, called resistant starch. Combine that with sourdough's fermentation benefits and you've stacked two things working in your favor before the bread even reaches your plate.

The real key: what you put on it and next to it

This is the part I want you to remember more than anything else in this post. Even the best sourdough is still a carbohydrate. If you eat it alone, on an empty stomach, you will still get a blood sugar rise.

Pair it with real protein and healthy fats instead, and you slow down how quickly that bread digests, which means a steadier blood sugar response instead of a spike and a crash. Real butter, a soft egg, smoked salmon, or a spread built around collagen protein and healthy fats all do this well. It's why I built a recipe around exactly that idea: toasted sourdough with a whipped tomato basil spread, real cream cheese, olive oil, and Yonder Flavorless Collagen Peptides folded in for extra protein.

When you don't have time to make your own

I don't always have a starter going, and that's alright. When I want good sourdough without baking it myself, I go to a local bakery that actually ferments its dough the traditional way, not a grocery store loaf labeled "sourdough" that's really just white bread with a little vinegar added for tang.

My go-to is Daily Bread Co., a small, faith-centered bakery in San Clemente, California. My daughter Grace works there, and I love watching her pull the day's dough from proofing before it goes in the oven. It's a genuinely small, family feel operation, organic ingredients, no shortcuts, and it happens to be run by people who share our values.

If you have a bakery like that near you, or a farmers market vendor doing real sourdough, that is always going to beat anything in a plastic bag at the store. Ask around. Read the ingredient list. If it lists more than flour, water, salt, and starter, keep looking.

And once you have a good loaf in hand, don't stop at plain butter. Pairing your toast with real protein and healthy fat is what actually keeps your blood sugar steady, so I built a recipe around doing exactly that: Tomato Basil Collagen Cream Cheese Toast, made with a whipped tomato basil spread folded with Yonder Flavorless Collagen Peptides.

Frequently Asked Questions

Is sourdough bread good for blood sugar?
According to PubMed research, sourdough fermentation has been shown to produce a lower rise in blood glucose and insulin compared to conventional bread in several human studies, largely because the organic acids created during fermentation slow how quickly the starch digests (Ramel et al., 2012, DOI).

Why is sourdough easier to digest than regular bread?
The long fermentation process breaks down a portion of the gluten and gliadin proteins in wheat before you eat it, and the lactic acid bacteria in the starter overlap closely with bacteria already found in the human gut (Rizzello et al., 2013, DOI; Gobbetti et al., 2016, DOI).

Can I eat sourdough bread every day?
I recommend treating it like any real carbohydrate: enjoy it, but pair it with protein and healthy fats so you're not eating it alone on an empty stomach. That combination supports a steadier blood sugar response than bread by itself.

Is sourdough gluten-free?
No. Traditional sourdough still contains gluten. Fermentation reduces some of the gluten and gliadin content and may make it easier for some people to tolerate, but it is not safe for anyone with celiac disease or a diagnosed gluten allergy.

Does freezing and toasting sourdough change how healthy it is?
Yes, in a good way. Cooling or freezing bread causes some of its starch to convert into resistant starch, a form that digests more slowly. Slicing, freezing, and toasting from frozen is a simple habit that works in your favor.

How do I find good sourdough bread if I'm not baking my own?
Look for a local bakery or farmers market vendor that lists only flour, water, salt, and a live starter, no shortcuts, no added commercial yeast to speed things up. That's the same standard I use when I buy from Daily Bread Co. in San Clemente.

About Sheri Geoffreys

Sheri Geoffreys is a cancer survivor, the Founder of Yonder, and a Certified Health Coach. She built Yonder alongside her childhood best friend, Gina, after her own health journey turned into a passion for clean, grass-fed collagen. Today she helps women feel strong, nourished, and confident from the inside out, one simple, real-food habit at a time. Explore Yonder's grass-fed collagen peptides or shop our collagen for women 30+ collection.

If you want to add protein to your toast the way I do, the whipped tomato basil spread in my Tomato Basil Collagen Cream Cheese Toast recipe folds in a scoop of Yonder Flavorless Collagen Peptides, real protein you won't taste, stirred right into the cream cheese.

Read more about Our Story or visit Sheri's author page.

References

1. Ramel A, Gudmundsdottir FD, Thorsdottir I. Effects of two different types of fast food on postprandial metabolism in normal and overweight subjects. Eur J Clin Nutr. 2012. DOI: 10.1038/ejcn.2012.125
2. Liljeberg H, Björck I. Bioavailability of starch in bread products. Postprandial glucose and insulin responses in healthy subjects and in vitro resistant starch content. Eur J Clin Nutr. 1994. PMID 8194500
3. Rosén LAH, et al. Endosperm and whole grain rye breads are characterized by low post-prandial insulin response and a beneficial blood glucose profile. Nutr J. 2009. DOI: 10.1186/1475-2891-8-42
4. Ribet L, et al. Nutritional benefits of sourdoughs: A systematic review. Adv Nutr. 2022. DOI: 10.1016/j.advnut.2022.10.003
5. Gobbetti M, et al. Drivers for the establishment and composition of the sourdough lactic acid bacteria biota. Int J Food Microbiol. 2016. DOI: 10.1016/j.ijfoodmicro.2016.05.022
6. Lau SW, et al. Sourdough Microbiome Comparison and Benefits. Microorganisms. 2021. DOI: 10.3390/microorganisms9071355
7. Arendt EK, Ryan LAM, Dal Bello F. Impact of sourdough on the texture of bread. Food Microbiol. 2006. DOI: 10.1016/j.fm.2006.07.011
8. Rizzello CG, et al. Use of fungal proteases and selected sourdough lactic acid bacteria for making wheat bread with an intermediate content of gluten. Food Microbiol. 2013. DOI: 10.1016/j.fm.2013.06.017
9. Menezes LAA, et al. Label-free quantitative proteomics to exploit the impact of sourdough fermentation on reducing wheat allergenic fractions. Food Chem. 2023. DOI: 10.1016/j.foodchem.2023.137037
10. Nieto JA, et al. Sourdough bread enriched with exopolysaccharides and gazpacho by-products modulates in vitro the microbiota dysbiosis. Int J Biol Macromol. 2024. DOI: 10.1016/j.ijbiomac.2024.132906

According to PubMed, all clinical citations above are sourced from peer-reviewed literature via the PubMed database, DOI links included per PubMed's attribution requirement.

These statements have not been evaluated by the Food and Drug Administration. This content is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease.