How many calories are in 40g of sourdough bread?

November 29, 2025 •

4 min read

According to nutritional databases, a single 40g slice of plain sourdough bread contains approximately 95 to 109 calories, though this can fluctuate based on the ingredients used. Understanding how many calories are in 40g of sourdough bread requires looking beyond the number, considering the broader nutritional profile and the unique fermentation process.

Quick Summary

A 40g portion of sourdough bread typically contains around 100 calories, with the precise amount varying due to ingredients and preparation.

Key Points

Average Calorie Count: A 40g slice of plain sourdough bread contains approximately 100 calories, a figure that can vary by recipe and flour type.
Ingredient Impact: Additions like whole grains, seeds, nuts, or cheese will increase the overall calorie and fat content of the bread.
Fermentation Benefits: The natural fermentation process of sourdough can improve digestibility and nutrient absorption, and lower the bread's glycemic index compared to conventional breads.
Phytic Acid Reduction: Sourdough fermentation reduces phytic acid, an 'anti-nutrient' found in grains, which allows for better absorption of minerals like iron, zinc, and magnesium.
Homemade Calculation: For precise calorie counting of homemade sourdough, calculate total ingredient calories and divide by the final baked weight of the loaf.
Beyond Calories: Consider the broader health benefits, such as better blood sugar control and prebiotic fiber, rather than just focusing on the raw calorie number.

Understanding the Caloric Content of Sourdough Bread

For those managing their dietary intake, understanding the calorie count of everyday foods is essential. For sourdough, a popular artisanal bread, the number of calories in a standard 40g serving is relatively consistent but can be influenced by several key factors. On average, a 40g slice of plain sourdough bread provides about 100 calories. This value is comparable to other similar breads, but the composition and health benefits of sourdough are what truly distinguish it.

What Influences Sourdough's Calorie Count?

The total calorie count of sourdough is not a single, fixed number. It can be affected by the specific recipe and production method. Several variables play a role:

Type of Flour: A sourdough loaf made with whole wheat or other whole grain flours will typically have more fiber and slightly different calorie and nutrient densities compared to a loaf made with refined white flour. While the difference in a small 40g serving is minor, it is notable over time. Whole grain varieties often pack more nutrients per calorie.
Hydration Level: The water-to-flour ratio, known as hydration, affects the dough's density. A higher hydration dough might result in a loaf that feels lighter and has a different crumb structure, but the total calories are still determined by the total mass of the baked bread.
Added Ingredients: Some artisanal sourdoughs include ingredients like seeds, nuts, olives, or cheese. These additions can significantly increase both the calorie and fat content per 40g slice. For example, a seed-studded sourdough will have more calories than a plain one due to the added fats and protein from the seeds.
Fermentation Process: The long fermentation process inherent to sourdough baking slightly changes the bread's composition, potentially leading to a slight reduction in carbohydrates and altering its glycemic index. The microbes in the starter consume some of the starches during fermentation, though this has a minimal impact on the final total calories per gram.

Sourdough vs. Other Common Breads: A Nutritional Comparison

Comparing sourdough bread to other popular bread types highlights its unique nutritional properties. While the calorie counts might be similar, the benefits of the fermentation process make a difference. Here is a comparison based on typical 40g serving sizes:


Bread Type	Approximate Calories per 40g	Key Benefit	Potential Drawback
Sourdough (White)	100-109 kcal	Lower glycemic index	Slightly higher calories than some fortified white breads
Sourdough (Whole Wheat)	95-104 kcal	Richer in fiber and nutrients	Can be denser; may not be suitable for those with high gluten sensitivity
Standard White Bread	Approx. 95 kcal	Soft texture; readily available	Lower fiber; higher glycemic index
Standard Whole Wheat Bread	Approx. 101 kcal	Higher fiber content	Can be less palatable for some; shorter shelf life
Multigrain Bread	Approx. 106 kcal	High in fiber and various nutrients	Calorie content varies widely; can contain added sugars

Calculating Calories for Homemade Sourdough

Calculating the precise calorie count for homemade sourdough requires a bit more effort, as recipes and ingredients vary. However, a reliable method focuses on the total ingredients and the final baked weight. The general steps are as follows:

Add up all ingredient calories: Look up the calorie information for every component in your recipe (flour, water, salt, starter). For the starter, you can approximate based on its flour and water content.
Determine total calories for the loaf: Sum the calorie counts of all the ingredients to get the total for the entire loaf.
Weigh the finished loaf: Weigh the cooled bread in grams after baking. The weight will be less than the starting dough due to moisture loss.
Calculate calories per gram: Divide the total calories by the final weight of the baked bread to find the calories per gram.
Multiply by serving size: To find the calories in your 40g portion, simply multiply the calories per gram by 40.

Following this process ensures a more accurate measure for homemade goods than relying on general averages.

Sourdough: A Nutritious Choice Beyond the Calorie Count

Beyond just the calories, sourdough bread offers several health advantages, mainly due to its unique fermentation process. While not a low-calorie food, it brings benefits to the table that commercial breads often lack:

Enhanced Digestibility: The slow fermentation process helps break down gluten and other complex carbohydrates, making sourdough easier for many people to digest. The lactic acid bacteria present in the dough start the pre-digestion process, reducing the burden on the consumer's digestive system.
Improved Nutrient Absorption: The fermentation process significantly reduces the level of phytic acid, a compound found in grains that can inhibit mineral absorption. By deactivating phytates, sourdough makes minerals like iron, zinc, and magnesium more bioavailable to the body.
Rich in Nutrients and Prebiotics: Sourdough is a good source of several vitamins and minerals, including B vitamins, folate, iron, and selenium. While the baking process kills the beneficial bacteria (meaning it isn't a probiotic source), the fiber acts as a prebiotic, feeding the good bacteria in your gut.
Lower Glycemic Index: Sourdough's fermentation produces organic acids that may help slow down the release of glucose into the bloodstream, leading to a lower and slower rise in blood sugar levels compared to conventional bread. This can be particularly helpful for managing blood sugar.

Conclusion: A Balanced Perspective on Sourdough

For those interested in how many calories are in 40g of sourdough bread, the answer is generally around 100 calories, a figure that places it in a similar range to other breads. However, focusing solely on calories misses the bigger picture. Sourdough's long fermentation offers unique advantages, including improved digestibility, enhanced nutrient absorption, and a lower glycemic index. These factors can make it a more wholesome and satisfying choice than many other bread options. When making or choosing sourdough, consider the ingredients, especially opting for whole grain versions to maximize the nutritional benefits. As with any food, moderation is key, and understanding the full nutritional profile allows for more informed dietary decisions.

Visit Healthline for more detailed nutritional information on sourdough.

Frequently Asked Questions

Sourdough bread often has a comparable calorie count to regular white bread per serving. The main nutritional benefits of sourdough lie in its fermentation process, which can enhance digestibility and nutrient absorption, rather than providing significantly fewer calories.

Generally, whole wheat sourdough is considered more nutritious than white sourdough. It contains more fiber, vitamins, and minerals. However, both varieties benefit from the fermentation process, which lowers the glycemic index and improves digestibility.

Sourdough bread is not typically considered a low-calorie food. While it has numerous health benefits, it remains a source of carbohydrates and has a moderate calorie density, similar to many other types of bread.

The fermentation process has a minimal effect on the total calories. The wild yeast and bacteria consume some starches, but the final calorie count is primarily determined by the ingredients. Its main impact is on the bread's nutritional profile and digestibility, not its overall energy content.

Yes, adding seeds, nuts, or other ingredients will increase the total calories and fat content. These additions can also boost the bread's nutritional value by adding healthy fats, fiber, and protein.

The calorie information on commercial sourdough labels is generally quite accurate, as it is calculated from standardized recipes. For homemade sourdough, calorie counts can vary and are best determined by calculating based on specific ingredients and final loaf weight.

While sourdough bread isn't a magic weight loss food, its lower glycemic index and increased satiety (feeling of fullness) compared to other breads may support weight management as part of a balanced diet. Portion control is still important.