Carb Counts and Health Benefits of Portobello Mushrooms

Nutritional information and glycemic load of portobello mushrooms

Portobello Mushrooms
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Portobello mushrooms are simply grown-up crimini mushrooms. Portobello mushrooms (especially the large ones) can be used as healthy alternatives for many food favorites when you are trying to eat less carbohydrate or trying to eat gluten-free.

For example, the large caps of portobello mushrooms can serve as vehicles for other ingredients such as pizza toppings, brown rice, quinoa, or other low-carb and gluten-free healthy grains.

Because of their texture, portobellos make a delicious and hearty meat alternative to a vegetarian or vegan. Grilled portobellos can be used instead of hamburger buns. These mushrooms also take well to marinades that provide more flavor.

When cooking with portobello mushrooms, many prefer to remove the gills, as they can turn very dark and exude liquid which muddies the flavors of the other ingredients.

Carbohydrate and Fiber Counts for Portobello Mushrooms

1/2 cup diced raw portobello mushrooms1.5 grams effective (net) carbohydrate plus 0.5 grams fiber and 11 calories
1 large portobello cap (about 3 ounces)3 grams effective (net) carbohydrate plus 1 gram fiber and 22 calories
1/2 cup sliced grilled portobello mushrooms1.5 grams effective (net) carbohydrate plus 1.5 grams fiber and 21 calories

Glycemic Index for Portobello Mushrooms

As with most non-starchy vegetables, there is no scientific study of the glycemic index of mushrooms.

Their glycemic index, which indicates how they affect blood sugar, is presumed to be very low as they lack sugars and starches.

Estimated Glycemic Load of Portobello Mushrooms

The glycemic load takes into account both the glycemic index and the amount of food that is eaten. A glycemic load of 10 or less is considered to be low and should have little effect on blood glucose or insulin response.

Portobello mushrooms and other mushrooms have a low glycemic load.

Serving SizeEstimated Glycemic Load
1/2 cup diced raw portobello mushrooms1
1 large portobello cap (about 3 ounces)2
1/2 cup sliced grilled portobello mushrooms2

Health Benefits of Portobello Mushrooms

Portobello mushrooms are an excellent source of copper, selenium, riboflavin, and niacin, and a very good source of pantothenic acid, potassium, and phosphorus. They are a good source of thiamin.

Low-Carb Mushroom Recipe

You can substitute portobello mushrooms (or the smaller variety known as crimini mushrooms) for the white button mushrooms in recipes and vice versa.

  • Crustless smoked salmon, leek, and mushroom quiche: Most quiches are made with high-carb crusts but a crustless version is easy to make and great for any meal. You can rethink any of your quiche recipes and bake them without the crust. You can even control your portion sizes by baking them in silicone muffin forms.


Atkinson FS, Foster-Powell K, Brand-Miller JC. International Tables of Glycemic Index and Glycemic Load Values: 2008. Diabetes Care. 2008;31(12):2281-2283. doi:10.2337/dc08-1239.

USDA National Nutrient Database for Standard Reference, United States Department of Agriculture.