How many calories does a cooked mushroom have? A detailed look at nutrition and preparation

November 5, 2025 •

3 min read

Mushrooms are a low-calorie food, with raw white button mushrooms containing only about 20 calories in a 3-ounce serving. The precise answer to how many calories does a cooked mushroom have? depends heavily on the cooking method, as preparation can significantly alter the final nutritional count.

Quick Summary

The calorie count for cooked mushrooms varies, primarily based on whether fat is added during preparation. While naturally low-calorie, methods like frying can increase the total. Boiling, grilling, or microwaving best preserve their low-calorie nature and high nutrient profile, offering a healthy dietary addition for weight management.

Key Points

Cooking Method is Key: How you prepare mushrooms, especially whether you add fat, is the main factor determining the final calorie count.
Naturally Low-Calorie: Raw mushrooms are very low in calories, and methods like boiling, steaming, and microwaving preserve this quality.
Oil Increases Calories Significantly: Sautéing or frying mushrooms with butter or oil dramatically increases the calorie total due to the mushroom's absorption of fat.
Grilling is a Healthy Option: Grilling or microwaving is an excellent way to cook mushrooms, preserving their low-calorie profile and antioxidant content.
Nutrient Powerhouse: Beyond low calories, cooked mushrooms provide important nutrients like B vitamins, potassium, and beneficial antioxidants.
Measure Accurately: Due to water loss during cooking, a volumetric measurement like a cup of cooked mushrooms will contain more actual mushroom (and calories) than a cup of raw mushrooms.
Better Nutrient Retention: Studies suggest that grilling and microwaving are better for retaining the antioxidant content of mushrooms compared to boiling or frying.

How Cooking Affects Mushroom Calories

Unlike many other foods, the calorie count of mushrooms isn't a single, fixed number after they've been cooked. This is because mushrooms are porous and absorb surrounding liquids and fats during the cooking process. A raw mushroom is mostly water, and as this water evaporates, the mushroom shrinks, concentrating its nutrients. The method of cooking—and crucially, what is added to the pan—is the most significant factor in determining the final calorie total.

Calories in Mushrooms Without Added Fat

When mushrooms are cooked without oil or butter, their calorie count remains very low. Methods like steaming, boiling, or microwaving are ideal for those strictly monitoring their intake. Since these methods don't introduce external fat, the calorie increase is minimal and primarily due to the concentration of the mushroom's natural nutrients as moisture is lost. For example, 100 grams of white button mushrooms, cooked via boiling and drained, contains approximately 28 to 48 calories, depending on the source. This demonstrates how even without added fats, the process of cooking concentrates the mushroom, slightly increasing the calories per gram relative to its raw state.

Calories in Mushrooms with Added Fat

This is where the calorie count can jump significantly. When you sauté or fry mushrooms in oil or butter, they act like a sponge, absorbing the fat. Since fat is dense in calories (about 9 calories per gram), this absorption dramatically raises the total. According to MedicineNet, 100 grams of mushrooms cooked in oil can range from 80 to 95 calories, a notable increase from the fat-free preparation. The specific calorie count will vary depending on the amount and type of fat used.

Other Nutritional Benefits of Cooked Mushrooms

Regardless of the cooking method, mushrooms remain a nutritional powerhouse, packed with vitamins and minerals. Cooking can sometimes even enhance their health benefits. For instance, some cooking methods can increase their antioxidant activity.

Rich in B-vitamins: They are an excellent source of B vitamins like riboflavin (B2), niacin (B3), and pantothenic acid (B5), which are essential for converting food into energy and maintaining healthy skin and nerves.
High in Minerals: Cooked mushrooms provide a good amount of minerals such as potassium, copper, and selenium. Potassium is vital for blood pressure control, while selenium and copper are powerful antioxidants.
Antioxidant Power: Mushrooms contain antioxidants such as ergothioneine and glutathione, which may protect the body against free radical damage and reduce the risk of certain chronic diseases.
Immune Support: The beta-glucans found in mushrooms have been shown to have immune-boosting properties.

Calorie Comparison: Cooking Method Matters

To illustrate the impact of cooking on calorie content, consider the following comparison based on 100g servings of cooked mushrooms.


Cooking Method	Approximate Calories per 100g	Key Impact on Calories
Boiled (no salt)	~28-44	Minimal increase; water loss concentrates nutrients.
Microwaved	~35	Minimal increase; similar to boiling.
Sautéed (with oil/butter)	~80-95	Significant increase due to absorbed fat.
Grilled (minimal oil)	Similar to microwaved/boiled	Low calorie, especially when a minimal amount of olive oil is used.
Deep-fried	~45-60 (plus coating calories)	Highest calorie option due to fat absorption.

It's also important to note that studies show microwaving and grilling are the best methods for preserving the nutritional value and antioxidant activity of mushrooms, while boiling and frying can lead to greater losses.

The Role of Serving Size

When counting calories, consider the effect of water loss. A cup of raw mushrooms contains fewer mushrooms by weight than a cup of cooked ones, as cooking causes them to shrink. For the most accurate calorie count, weigh your mushrooms before cooking or use a nutrient database that specifies the cooking method and serving size. Ultimately, the best method for calorie control is to measure your fat intake and choose cooking techniques that use minimal oil. For more information on dietary needs, you can visit the U.S. Department of Agriculture's FoodData Central database.

Conclusion

So, how many calories does a cooked mushroom have? The answer is that it varies. Cooked mushrooms can be an incredibly low-calorie addition to your diet when prepared simply through boiling, steaming, microwaving, or grilling. These methods best preserve their low-fat nature and maximize their nutritional benefits. However, adding oil or butter through sautéing or frying can significantly increase the calorie count due to fat absorption. By being mindful of your cooking method, you can enjoy the earthy flavor and health benefits of mushrooms without derailing your diet.

Frequently Asked Questions

For mushrooms cooked without added fat, such as by boiling or microwaving, the calorie count per 100g is typically between 28 and 48 calories. This range can vary slightly depending on the mushroom variety and preparation.

Cooking itself doesn't add calories, but the method of cooking can. If you sauté or fry mushrooms in oil or butter, the fat is absorbed, increasing the calorie count significantly.

Both raw and cooked mushrooms offer health benefits. However, cooking, particularly grilling and microwaving, has been shown to increase the antioxidant activity of some mushrooms. Cooking also makes mushrooms easier to digest and eliminates certain potential toxins present in raw fungi.

Sautéing mushrooms significantly increases their calorie count because they absorb the oil or butter used in the pan. A serving of sautéed mushrooms can have double or triple the calories of a boiled or microwaved serving.

For a low-calorie diet, the best cooking methods for mushrooms are grilling, microwaving, or boiling. These techniques preserve the mushroom's low-fat content and often enhance its nutritional properties without adding extra calories.

Yes, while generally low, the specific calorie counts can vary slightly between different types of mushrooms. For instance, raw sliced oyster mushrooms contain 28 calories per cup, while a different variety might have more or less.

Some nutrients, particularly water-soluble vitamins, can be lost during boiling. However, other cooking methods like grilling and microwaving are more effective at preserving nutrients and can even enhance antioxidant activity.