Calories in Sourdough Bread: Nutrition Facts & Serving Sizes
Per 1 slice (139g)
Per 100g
Source: USDA FoodData Central, SR Legacy, March 2026.
A slice of sourdough bread (based on a 1 oz serving, 28g) contains about 77 calories with 3.1g of protein and 14.7g of carbs. Per 100g, sourdough bread provides 272 calories with 10.8g of protein, 2.4g of fat, and 51.9g of carbs. Sourdough is made through lacto-fermentation with wild yeast and bacteria, giving it a tangy flavor and a lower glycemic impact than regular bread. The selenium content is strong at 28.6mcg per 100g and iron at 3.9mg per 100g, covering about 22% of the daily iron target. Folate is notable at 170mcg per 100g, supporting DNA synthesis and cell health. Sourdough contains 2.2g of fiber per 100g. Compared to white bread (265 cal/100g), sourdough has similar calories but higher protein and lower glycemic index due to the fermentation process. For anyone tracking macros, sourdough is a more nutritious bread choice that is especially useful when you want bread that does not spike blood sugar as sharply.
Nutrition Highlights
Calories by Serving Size
| Serving | Cal | Protein | Carbs | Fat | Fiber |
|---|---|---|---|---|---|
| 1 oz (28g) | 77.2 | 3.1g | 14.7g | 0.7g | 0.6g |
| 1 slice (139g) | 378.1 | 15g | 72.1g | 3.3g | 3.1g |
| 100g | 272 | 10.8g | 51.9g | 2.4g | 2.2g |
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Full Nutrition Facts (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 272 | 14% |
| Protein | 10.8g | 22% |
| Total Fat | 2.4g | 3% |
| Saturated Fat | 0.5g | 3% |
| Total Carbohydrates | 51.9g | 19% |
| Dietary Fiber | 2.2g | 8% |
| Sugars | 4.6g | 9% |
| Sodium | 602mg | 26% |
Vitamins & Minerals (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Saturated Fat | 0.5g | 0% |
| Calcium | 52mg | 4% |
| Iron | 3.9mg | 22% |
| Potassium | 117mg | 2% |
| Vitamin B6 | 0.1mg | 6% |
| Magnesium | 32mg | 8% |
| Phosphorus | 105mg | 8% |
| Zinc | 1mg | 9% |
| Selenium | 28.6mcg | 52% |
| Folate | 170mcg | 43% |
| Thiamin (B1) | 0.7mg | 58% |
| Riboflavin (B2) | 0.4mg | 31% |
| Niacin (B3) | 4.8mg | 30% |
% Daily Values based on a 2,000 calorie diet (FDA reference).
Health Benefits of Sourdough Bread
Sourdough bread is fermented using wild yeast and lactic acid bacteria, which changes the nutritional profile compared to commercial yeasted bread. The fermentation process breaks down phytic acid in flour, which normally binds minerals like zinc and magnesium and reduces their absorption. Sourdough fermentation improves mineral bioavailability compared to regular bread.
The lower glycemic index of sourdough (around 54, compared to 70+ for white bread) means it produces a slower, more gradual rise in blood sugar. For those managing insulin sensitivity or energy levels throughout the day, sourdough causes less of the blood sugar spike-and-crash cycle associated with white bread and regular sandwich bread.
Sourdough provides 28.6mcg of selenium per 100g, 3.9mg of iron per 100g, and 170mcg of folate per 100g. These are meaningful micronutrient contributions for a bread product. The iron and folate are important for red blood cell production and oxygen transport, which directly impacts training performance and recovery.
The fermentation process also partially breaks down gluten proteins, which can make sourdough more digestible for people with mild gluten sensitivity (though it is NOT safe for celiac disease). The live bacteria in uncooked sourdough starter provide probiotic benefits, though baking kills most active cultures.
Dietary Considerations
Sourdough bread contains gluten and is not safe for celiac disease. It is not vegan-free (most traditional recipes are vegan) but does contain gluten. Not keto-friendly at 51.9g of carbs per 100g. For weight loss, sourdough is a better bread choice than white bread due to its lower glycemic index, higher protein, and better satiety. The high sodium content (602mg per 100g) is worth noting for those on a sodium-restricted diet.
Daily Intake (100g)
100g of sourdough bread provides 14% of a 2,000-calorie diet.
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Frequently Asked Questions
How many calories in sourdough bread?
A 1 oz serving of sourdough (28g) has about 77 calories. Per 100g, sourdough contains 272 calories. A standard large slice (about 50g) has roughly 136 calories.
Is sourdough bread good for weight loss?
Sourdough is a relatively good bread choice for weight loss compared to white bread. Its lower glycemic index means more stable blood sugar and better satiety. However, it still contains significant carbs (51.9g per 100g) and should be portioned carefully on a calorie deficit.
How much protein in sourdough bread?
Sourdough contains 10.8g of protein per 100g. A 1 oz serving has 3.1g of protein. This is higher than most white breads, which average around 8 to 9g of protein per 100g.
Is sourdough bread gluten-free?
No, sourdough bread is made from wheat flour and contains gluten. It is not safe for people with celiac disease. The fermentation process breaks down some gluten proteins, but not enough to make it celiac-safe.
Is sourdough bread healthier than white bread?
Sourdough is generally considered healthier than white bread. It has a lower glycemic index (around 54 vs 70+ for white bread), higher protein, and better mineral bioavailability due to the fermentation process that breaks down phytic acid.
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