How many calories in a slice of toasted sourdough bread?

November 20, 2025 •

3 min read

According to the USDA, a standard 1-ounce slice of sourdough white bread contains approximately 77 calories. This figure can be used to estimate how many calories in a slice of toasted sourdough bread, though the final count depends on the bread's specific weight and ingredients.

Quick Summary

The exact calorie count for a slice of toasted sourdough bread varies based on slice size, thickness, and ingredients. Toasting does not significantly alter the caloric content. Differences in preparation, such as using whole grain flour or adding toppings, can affect the nutritional value.

Key Points

Variable Calorie Count: The number of calories in a slice of toasted sourdough bread depends mainly on its weight and thickness, not the toasting process itself.
Toasting Removes Water: Toasting removes moisture, but it doesn't significantly change the slice's caloric or macronutrient content.
Calorie Spikes from Toppings: Most extra calories come from spreads and toppings like butter, cheese, or avocado, not the bread itself.
Lower Glycemic Index: Toasting can lower the bread's glycemic index, leading to a slower release of sugar into the bloodstream.
Choose Whole Grain: Sourdough made with whole-grain flour is often higher in fiber, which can increase feelings of fullness and aid digestion.
Manage Portions for Control: Slicing the bread more thinly is a simple way to manage and control your overall calorie intake.

Sourdough's Caloric Content Explained

Sourdough bread's unique tangy flavor comes from a long fermentation process involving a natural leavening agent made of wild yeast and good bacteria. When considering the caloric content, it's important to understand that the number of calories isn't set in stone. It depends on several variables, with the weight of the slice being the most critical factor. A heavier, thicker slice will inevitably contain more calories than a thinner one. For example, a standard 1-ounce (28g) slice contains about 77 calories, but a larger, 2-ounce (59g) slice could have closer to 188 calories.

Does Toasting Affect Calories?

A common misconception is that toasting bread reduces its calorie count. This is not the case. The toasting process primarily removes water through evaporation. While this changes the bread's texture and density, it doesn't significantly change the caloric value of the food itself. The total energy potential remains largely the same unless the bread is burnt to a crisp, a situation where carbonization would render a small amount indigestible, but this isn't relevant to normal consumption. A key benefit of toasting is that it can lower the bread's glycemic index (GI), causing carbohydrates to break down more slowly and preventing a sharp spike in blood sugar levels compared to untoasted bread.

Factors Influencing Sourdough Calories

The overall calorie count for your toasted sourdough can shift depending on several factors:

Slice Thickness: Thicker slices mean more bread per serving, which means more calories. Pay attention to how the bread is cut.
Flour Type: Breads made with different flours will have varying nutritional profiles. Whole-grain sourdough typically contains more fiber and nutrients than white sourdough, which can affect its overall impact on digestion and fullness.
Added Ingredients: Some sourdough recipes include additions like seeds, honey, or milk, all of which will increase the final calorie count.

Standard Caloric Breakdown of Sourdough

Here is a general nutritional overview based on data from sources like Nutritionix and the USDA for a standard slice of sourdough toast:


Nutrient	Approx. Value per 1-ounce slice	Approx. Value per 2-ounce slice
Calories	77	188
Carbohydrates	15 g	37 g
Protein	3 g	8 g
Fat	<1 g	1 g
Fiber	1 g	2 g

How to Calculate Calories for Your Specific Bread

For the most accurate calorie count, especially if you're baking homemade sourdough, you can do a simple calculation. First, determine the total calories of all your ingredients. Second, weigh your finished loaf after it has cooled completely. Then, divide the total calories by the weight of the loaf in grams to find the calories per gram. Finally, weigh your slice and multiply it by the calories per gram.

Making Healthier Toasted Sourdough Choices

Go Whole Grain: Choosing a sourdough made with whole-grain flour increases fiber content, which promotes satiety and aids digestion.
Manage Toppings: The majority of added calories often come from spreads. A tablespoon of butter, for instance, can add about 100 calories. Opt for lighter toppings like avocado, a drizzle of olive oil, or a sprinkle of nutritional yeast for fewer calories.
Control Portion Size: Simply cutting smaller, thinner slices can help control your calorie intake without having to give up your favorite toast.

Conclusion

While a definitive answer to "how many calories in a slice of toasted sourdough bread?" depends on the specific loaf, a standard 1-ounce slice contains roughly 77 calories, with a larger slice containing more. The toasting process itself does not alter the core caloric value but can make the bread easier to digest. Ultimately, the total caloric impact on your diet is most affected by portion size and your choice of toppings. By being mindful of these factors, you can enjoy this delicious and healthy bread as part of a balanced diet.

For Further Reading

USDA FoodData Central - The USDA's comprehensive nutrition database can provide additional nutritional information for a wide variety of foods, including sourdough bread, based on standard food entries. This is an authoritative resource for general nutrient data.

Frequently Asked Questions

No, toasted sourdough does not have more calories than untoasted bread. Toasting removes water but does not change the core caloric value of the bread.

Whole wheat sourdough and white sourdough have fairly similar calorie counts. However, whole wheat versions are higher in fiber and nutrients.

Calorie counts vary online because they depend on slice size and weight. A small, thin slice will have fewer calories than a large, thick one, leading to different figures across various sources.

Yes, you can accurately track homemade sourdough calories. Weigh your cooled loaf after baking, sum the total calories from your ingredients, and divide the total by the loaf's weight to get calories per gram. Then, weigh each slice.

Yes, adding butter or avocado significantly increases calories. For example, one tablespoon of butter can add approximately 100 calories to your slice of toast.

Sourdough bread has a lower glycemic index than conventional white bread due to the fermentation process. Toasting it further lowers the glycemic index, helping to prevent sharp blood sugar spikes.

Sourdough toast can be a healthier choice than regular toast. The fermentation process can reduce phytic acid, improving nutrient absorption. Toasting also gives it a lower glycemic index.