Sourdough Vs. White Bread: Which Is Healthier? Dietitians Explain

You typically can’t find sourdough among the rectangular, uniformly shaped loaves lining the bread aisle. Instead, sourdough is usually in the bakery section of the grocery store, and the slices tend to be larger, making it tricky to compare sourdough vs. white bread slice-for-slice. Below, you’ll find facts for one slice of sourdough and two slices of white bread.

Sourdough nutrition

According to the U.S. Department of Agriculture (USDA), one medium slice (which is around 59 grams) of sourdough bread contains:

• 188 calories
• 7.67 g of protein
• 1.26 g of fat
• 36.5 g of carbohydrates
• 1.83 g of fiber

White bread nutrition

Per the USDA, two slices (about 55 g) of white bread contain:

• 146 calories
• 5.14 g of protein
• 1.96 g of fat
• 26.8 g of carbohydrates
• 1.26 g of fiber

Sourdough gets its chewy texture and tangy taste through fermentation, a process that creates live microorganisms, and these are what are responsible for its beneficial properties. For instance, fermentation generates prebiotics, which contribute to a balanced gut microbiome by feeding the good bacteria that reside there.

Sourdough also has a low glycemic index (GI), meaning it’s digested more slowly by the body, and in turn is less likely to spike blood sugar in the same way that white bread and other items made from refined flours do. “This makes sourdough especially good for those looking for a blood sugar-friendly option,” says Courtney Pelitera, M.S., R.D.N., C.N.S.C., a registered dietitian nutritionist at VNutrition. Research backs it up: sourdough bread created a smaller spike in blood glucose levels than non-fermented bread at both 60 and 120 minutes after consumption, according to research in Critical Reviews in Food Science and Nutrition.

The fermentation process also makes sourdough easier on your digestion, which may reduce the likelihood of you experiencing discomfort like bloating or gas, and as Pelitera explains it, fermentation also “reduces the amount of gluten present in sourdough,” so even people who are sensitive to gluten (but who don’t have full-blown celiac disease) may be able to scarf down sourdough with fewer gut issues.

Both the type of flour used to make sourdough and how long it ferments contribute to how healthy it is, explains Jamie Baham, M.S., R.D.N., L.D., a cancer prevention dietitian at Ladybug Nutrition. Sourdough made with whole-wheat flour, for instance, will contain more fiber than sourdough made with white flour—making it an even better option as a food to support blood sugar and smooth digestion. And while sourdough can be a smart pick for some people with gluten sensitivity, it’s not safe for those with celiac disease as it does still contain some gluten.

“White bread is a staple in many households,” says Pelitera. “It is a great option for toast or sandwiches.” White bread falls into the category of simple or refined carbohydrates, which means the nutrient-rich parts of the grain are stripped away during processing. However, “most white breads are enriched with B vitamins and iron,” Pelitera adds, so it can still be a decent choice sometimes.

“Enrichment is when you add back the nutrients lost through processing,” Baham explains. “Fortification is when you add nutrients that are not naturally available in the foods before processing to improve the nutrition content.” Choosing white bread that has either of these words on the label will ensure you’re getting the most out of your pick.

“Fiber is one of the nutrients not added back to bread after refining,” says Baham. “It’s one of those things that Americans are just not getting enough of, and white bread is severely lacking it.” The lack of fiber means that white bread is going to spike blood sugar levels faster than bread that contains more fiber, such as whole-wheat or multigrain, plus have less of an impact on your satiety, Pelitera adds. Translation: you may become peckish before your next meal, or sluggish due to the blood sugar spike and then inevitable crash.

Research in Frontiers in Nutrition has also linked daily consumption of white bread to a higher risk of heart attacks, suggesting that it’s indicative of an overall diet that may be harmful to heart health (and not necessarily strictly due to white bread as a food itself).

If your goal is weight loss, you can make toast or sandwiches with either sourdough or white bread, as “moderation is key no matter your diet,” says Baham. That said, “if you choose sourdough made from whole-wheat flour, the fiber content will be higher, potentially providing more satisfaction during that meal,” she adds. Increased feelings of fullness can help prevent overeating during meals and extra snacking afterward.

While both sourdough and white bread can be part of a healthy diet when enjoyed in moderation, Pelitera says that sourdough has an edge. “Sourdough is going to be more blood sugar-friendly, making it the healthier option between the two,” she explains. That’s especially the case if you can find whole-wheat sourdough, which will contain more fiber. Fiber content, a low glycemic index, and being gentle on the gut make sourdough the smarter choice.