Can you eat portobello mushrooms on keto diet?

The keto diet has become one of the most popular diets for weight loss and overall health in recent years. This low-carb, high-fat diet helps the body enter a state of ketosis, where it burns fat for fuel instead of carbs. When starting a keto diet, it’s important to understand which foods to eat and avoid. One food that often comes up is mushrooms, specifically portobello mushrooms.

What are portobello mushrooms?

Portobello mushrooms, also known as portabella mushrooms, are a large variety of agaricus bisporus mushrooms. They are mature brown mushrooms that have been allowed to fully grow and develop an open cap about 4-6 inches in diameter. Compared to regular white button mushrooms, portobellos have a meatier texture and more robust, savory flavor. When cooked, they take on a rich, almost steak-like taste. In addition to their size and taste, portobello mushrooms offer some nutritional benefits:

  • Low in calories – One large portobello mushroom contains only 42 calories
  • Good source of fiber – One mushroom has 5 grams of dietary fiber, important for digestive health
  • Provides nutrients – Portobellos contain B vitamins like riboflavin, niacin, and pantothenic acid. They also have minerals like potassium, phosphorus, selenium, and copper.
  • High in antioxidants – Contains antioxidant compounds like ergothioneine to help reduce oxidative stress

Thanks to their savory umami flavor when cooked, meaty texture, and nutritional value, portobello mushroom caps are often used as veggie burgers or vegetarian steak replacements. Their large size also makes them ideal for stuffing or grilling.

Are portobello mushrooms keto-friendly?

When following a ketogenic diet, the primary goal is to get your body into ketosis. This requires eating very few carbs, moderate amounts of protein, and high amounts of fat. Most ketogenic diets limit net carbs to 20-50 grams per day. So are portobello mushrooms able to fit into this low-carb requirement?

The simple answer is yes. Portobello mushrooms are a keto-friendly food.

Here’s a nutritional breakdown of 1 large portobello mushroom (about 1 cup sliced):

  • 42 calories
  • 3 grams protein
  • 0 grams fat
  • 7 grams carbs
  • 5 grams fiber
  • 2 grams net carbs

With only 2 net grams of carbs per mushroom, portobellos can easily be incorporated into a ketogenic diet. Their low calorie and high fiber content are also beneficial on keto.

Benefits of eating portobello mushrooms on keto

Including portobello mushrooms as part of your keto diet offers several benefits:

1. Low in carbs and calories

Portobellos provide very few net carbs and minimal calories, making them an ideal keto-friendly food. Consuming non-starchy vegetables like mushrooms can help keep carbs low while providing nutrients.

2. Source of fiber

Maintaining proper fiber intake on keto is important for digestive health. With 5 grams of fiber in each portobello mushroom, they can help meet daily fiber needs.

3. Provide key micronutrients

Nutrient deficiencies may occur on very low-carb diets. Portobello mushrooms contain antioxidants, B vitamins, selenium, potassium, and other vitamins and minerals that can help fill in nutrient gaps.

4. Aid in feeling full

One potential side effect of keto is increased hunger, especially when first adapting to the diet. Eating foods that are naturally high in volume and fiber like portobello mushrooms can help control hunger and cravings.

5. Versatile ingredient

The meaty texture and savory flavor of portobellos allow them to be versatile ingredients in keto recipes. They can provide volume and taste in dishes like vegetarian keto stir fries, fajitas, casseroles, soups, omelets, and more.

6. Easy to prepare

Portobello mushrooms require very simple preparation – just wipe clean with a damp towel, trim the stems, and they’re ready to cook and enjoy! Minimal prep makes them an easy addition to keto meals.

Potential downsides of portobello mushrooms

While portobello mushrooms have many benefits on a ketogenic diet, there are a couple potential downsides to consider:

1. High sodium content

Portobellos are one of the highest sodium mushrooms, containing about 28 milligrams per cup. People limiting sodium intake may want to be mindful of portion sizes.

2. Can absorb cooking liquid

The porous structure of portobello mushrooms means they can soak up any oil or cooking liquids used in recipes. This could potentially increase calories and fat grams if cooking with high fat ingredients.

3. May cause gastrointestinal discomfort

Some people may experience bloating or gas from eating larger amounts of mushrooms. This seems to be more common with raw mushrooms versus cooked.

Tips for eating portobellos on keto

Here are some tips to enjoy portobello mushrooms as part of your ketogenic diet:

  • Try using portobellos as burger buns or pizza crust for grain-free keto recipes.
  • Grill portobello caps on the barbecue as a healthy, low-carb steak alternative.
  • Sauté sliced mushrooms in coconut oil or avocado oil for a quick side dish.
  • Add chopped portobellos to omelets, frittatas, or scrambled eggs.
  • Mix with cauliflower rice and keto-friendly sauces for fried mushroom “rice”.
  • Stuff portobello caps with keto-friendly ingredients like cheese, sausage, zucchini, or spinach.
  • Use thinly sliced mushrooms in lettuce wrap sandwiches or tacos.
  • Make ahead and marinate portobello caps in olive oil, balsamic vinegar, garlic, and herbs for added flavor.
  • Watch sodium intake if consuming multiple portobello mushrooms per day.

Keto portobello mushroom recipes

Here are some delicious keto recipes featuring portobello mushrooms:

1. Portobello Pizza

Pizza Portobello caps topped with sauce, cheese, and keto toppings for a low-carb “pizza” substitute.

2. Portobello Fajitas

Sliced portobello mushrooms sautéed with onions and peppers for a sizzling veggie fajita platter.

3. Stuffed Portobellos

Portobello caps filled with creamy spinach, feta, and artichoke hearts for a quick vegetarian dinner.

4. Portobello Burgers

Use large grilled portobellos in place of buns for juicy keto-friendly burgers.

5. Mushroom Steak

Marinated, grilled portobello caps served with a savory butter sauce for a satisfying steak-like entrée.


Portobello mushrooms are a great choice to include as part of a ketogenic diet. With only 2 net grams of carbs and 5 grams of fiber per mushroom, they can fit into your daily carb limit. Portobellos also provide beneficial nutrients like antioxidants, B vitamins, and minerals. Their meaty texture makes them perfect for mimicking high-carb dishes, and they can be used in many different keto recipes. Just be mindful of potential downsides like high sodium content or gastrointestinal discomfort. Overall, portobello mushrooms are a tasty, low-carb way to boost your vegetable intake on the keto diet.

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