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Home » Recipes » Low Carb Recipes

Healthy Low Carb Tuna Casserole Recipe

Modified: Aug 5, 2020 by Kori Butler · Published: Jan 18, 2023

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This low carb keto tuna casserole is made extra delicious with tender cauliflower, fresh zucchini, a creamy herb sauce, chunky tuna, and layered with ooey gooey melted cheese. Sure to become a new family favorite - this healthy casserole is a high protein, gluten free, sugar free, keto-friendly dinner idea! It can also be made low fat and lighter with easy substitutions.

Tuna casserole garnished with fresh dill and diced tomatoes.Pin

Why You'll Love This Keto Tuna Casserole

Inexpensive. Using canned tuna makes for a very cost-effective meal! Also, because it is a pantry staple, it has a long shelf life and doesn't take up precious space in your fridge or freezer.

Delicious. The combination of tuna, dill, sauce, zucchini, and cheese make this a very delicious keto tuna casserole. The zucchini and cauliflower give it a fresh taste that balances the melted cheese and tuna.

Healthy. You'll love this healthy tuna casserole - it's high in protein, gluten-free, low carb, keto, and has no added sugar. Oh, and it's a great way to sneak in extra veggies! Between the cauliflower and zucchini, you have a full serving of vegetables in this recipe!

If not following keto, lower the fat by using a low-fat or fat-free sour cream and mayonnaise. Reduce the cheese to 1 cup.

Low Carb Tuna Casserole Ingredients

Here are the ingredients that you will need to make this casserole recipe:

  • Cooked Cauliflower - microwave, steamed, boiled, or roasted cauliflower (oven or air fryer) all work perfectly.
  • Canned Tuna - you can also use shrimp, crab, or salmon.
  • Celery
  • Green Onions - finely chopped shallots or red onion can be used in place of green onion.
  • Mayonnaise - use any favorite brand. It's fine to use a lower-fat variety if needed.
  • Sour Cream - same as the mayo, use a lower fat if needed.
  • Dijon Mustard
  • Fresh Dill - chives, basil, parsley, and thyme can also be used.
  • Kosher Salt - add according to the recipe and adjust after serving.
  • Ground Black Pepper
  • Zucchini
  • Shredded Jack or Cheddar Cheese - mozzarella, swiss, or gouda will work fine too.
  • Crushed Ground Pork Rinds - you can crush your own pork rinds or buy them already crushed.

Be sure to save this pin to Pinterest for later!

Cheesy tuna casserole served in a white rectangle baking dish.Pin

Tuna Casserole Keto and Low Carb Variations

  • Make this a keto seafood casserole - most canned seafood can replace the tuna - salmon, crab, and shrimp. A combination is also delicious.
  • Use a salted seafood seasoning in place of the salt. Adjust seasoning to taste with salt after serving.
  • Slice the zucchini or make zucchini noodles. I found it faster to slice then to make the zucchini noodles.
  • ¼ cup softened cream cheese can be added if desired.
  • Process keto bread in a food processor and use as breadcrumbs instead of pork panko.
  • Use a full fat, low fat, or fat free mayonnaise and sour cream - depending upon your dietary needs.
  • Add a little spice with some red pepper flakes or cayenne pepper.
  • Substitute broccoli for cauliflower.

How To Make Keto Tuna Casserole

Okay, this is so easy and good you will wonder why you have never made this before! 🙂 

Prep And Assemble Your Ingredients

Cook the cauliflower. Preheat your oven to 350 degrees. Drain the tuna and set aside. Chop your vegetables and assemble all other ingredients.

Make Tuna Mixture

In a bowl, combine cauliflower, drained tuna, celery, green onions, mayonnaise, sour cream, mustard, herbs, salt, and pepper.

Adding the salt and pepper to the tuna in a mixing bowl to make keto tuna casserole.Pin

Layer Zucchini and Cheese

In a buttered 1.5-quart baking dish, spoon half of the tuna and sauce mixture and spread evenly. Layer with half the zucchini and then half the cheese.

Top with the remaining half of the tuna, zucchini, and finish by topping with cheese.

Layering the mixture, zucchini, and cheese in a baking dish to make this healthy tuna casserole keto.Pin

Sprinkle top with pork rind panko.

Spinkling the top of the tuna casserole with pork rind panko.Pin

Bake

Bake for 40 minutes or until the dish is hot and the cheese is bubbly.

Let the casserole sit for about 5-10 minutes before serving.

Baking and then serving the tuna casserole.Pin

How To Serve Low Carb Keto Tuna Casserole

Garnish with fresh herbs.

  • Topping it with diced tomato and sometimes avocado is a great way to sneak in extra veggies!
  • Top it with a dollop of sour cream or additional shredded cheddar cheese, jack or parmesan cheese.
  • Meal idea! Serve your tuna casserole with a fresh green salad and this delicious Creamy Dill Dressing.

Top Tips

  • Slice the zucchini very thin to help it cook faster in the casserole.
  • Adjust any seasoning to taste.
  • Use 1 teaspoon dried herbs for every 1 tablespoon.
  • If the casserole is browning too fast, cover it with foil.
  • Crush your own pork rinds if you can't find the panko.
  • Use butter, olive oil, or cooking spray to coat the casserole dish.

FAQs

Is canned tuna good for a low carb diet?

Yes! Tuna is very low in carbs and is perfect on a low-carb and keto diet. It is also sugar-free and gluten-free.

How many carbs in tuna casserole?

The answer to that depends on which recipe you are following and can vary widely. This tuna casserole contains 4.8 grams of cabs, 1.4 g of fiber, and only 3.4 grams of net carbs.

Is tuna good for keto?

Yes, absolutely. Tuna has almost no carbs, sugar, and is gluten-free. Because it is lower in fat it is usually combined with healthy fats such as avocado, mayonnaise, cheese, etc.

How To Store

To store leftovers, let the casserole cool completely, then transfer to an airtight container. Store in the refrigerator for up to 4 days. See reheating instructions below.

How to Reheat

Oven: preheat oven to 350 degrees. Transfer the casserole to an oven-safe dish and cover it with foil. Bake until heated through, about 20 minutes.
Microwave: in a microwave-safe dish, cook covered for 1 to 2 minutes until heated through. Adjust heating time and temperature according to your microwave wattage.

Can I ask you a favor?

If you tried this recipe, let me know! I'd love for you to come back and give the recipe a 5 star rating and leave a review in the comments! 🙂 Let's stay connected, so please follow me on Instagram, Facebook, and Pinterest! Subscribe to my newsletter to get healthy fresh recipe ideas every week!

📖 The recipe.

Baked low carb tuna casserole in a white casserole dish.

Low Carb Keto Tuna Casserole Recipe

A very simple and tasty low carb and keto tuna casserole recipe! The zucchini, cauliflower, and herbs pair well with the melted cheese and tuna. Substitute salmon, shrimp, or crab for the tuna too!
4.75 from 12 votes
Print Recipe Pin Recipe Save Saved!
Author Kori Butler
Prep Time 15 minutes mins
Cook Time 40 minutes mins
Total Time 55 minutes mins
Course Casserole Recipes
Cuisine American
Servings 6 servings
Calories 332 kcal

Ingredients
  

  • 3 cups cooked cauliflower (florets about 1" to 1½" in size)
  • 2 (6.5-ounce) cans drained tuna (or, salmon, crab, or shrimp)
  • ½ cup chopped celery
  • ½ cup sliced green onions
  • ½ cup mayonnaise
  • ½ cup sour cream
  • 2 teaspoons dijon mustard
  • 1 tablespoon fresh dill (or, 1 teaspoon dried)
  • ½ teaspoon kosher salt
  • ¼ teaspoon pepper
  • 1 small zucchini (very thinly sliced)
  • 1½ cups shredded cheddar or jack cheese (or, mozzarella, swiss, gouda)
  • ¼ cup crushed pork rinds

Instructions
 

  • Preheat oven to 350 degrees. Prep and assemble your ingredients. Drain tuna (or other seafood), and set aside.
  • In a bowl, combine cauliflower, tuna, celery, green onions, mayonnaise, sour cream, mustard, dill, salt, and pepper.
  • In a buttered 1½-quart casserole dish, spoon half of the tuna mixture. Layer half the zucchini and half the cheese. Top with the remaining half of the tuna mixture and zucchini. Finish with cheese.
  • Sprinkle crushed pork rinds over the top. Bake at 350 degrees for 40 minutes until the dish is hot and cheese is bubbly.
  • Sprinkle with fresh dill and serve.

Video

Kori's Tips

  • Don't miss all of our helpful hints, substitution ideas, cooking tips, and other delicious recipes that can be found in our post. Check it out!
  • VARIATIONS: Substitute canned shrimp or salmon; use chives, parsley, or thyme in place of dill - or a mix; mozzarella, jack, or cheddar cheese can be used; green onion can be added to the casserole.
  • TIPS: Roasted (oven or air fryer), boiled, or steamed cauliflower will all work great. The best flavor is roasted cauliflower. Reduce the amount of salt called for when roasting.
  • SERVING SUGGESTIONS: Adjust salt and pepper. Garnish with fresh dill or chives and diced tomato.

 

 
 

Nutrition

Calories: 332kcalCarbohydrates: 4.8gProtein: 20.8gFat: 25.5gCholesterol: 49.7mgSodium: 721mgFiber: 1.4gSugar: 2.6g
DID YOU MAKE THIS RECIPE?Mention @seekinggoodeatsofficial or tag #seekinggoodeats! Be sure to subscribe to my newsletter to receive more healthy delicious recipes straight to your inbox.

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Reader Interactions

Comments

  1. Lori

    January 25, 2024 at 6:36 pm

    I made this and used a 1/4 cup Boursin cheese and 1/4 cup mayonnaise instead of the full 1/2 cup of mayo. I didn’t have zucchini so I used peas instead. Turned out great! I also roasted the cauliflower. Will make again.

    Reply
    • seekinggoodeats

      January 26, 2024 at 1:27 pm

      Thank you! That sounds fabulous and I'm totally going to try your idea. thanks for sharing! 🙂

      Reply
  2. Heather Rasmussen

    April 28, 2023 at 10:25 pm

    Tried this recipe tonight.. it was delicious!

    Reply
    • seekinggoodeats

      May 12, 2023 at 7:42 am

      Thank you! 🙂

      Reply
  3. Harvey

    January 24, 2021 at 11:47 pm

    I modified this recipe a lot for what I had on hand, but I really liked it as a basis for a non-pasta tuna casserole. Made it with cream of mushroom soup, broccoli instead of cauliflower, and mixed veggies instead of zucchini. Still very tasty! Will make again!

    Reply
    • Kori

      January 25, 2021 at 2:45 pm

      Sounds delicious and thank you! 🙂

      Reply
  4. Bobs Mom

    August 21, 2020 at 11:57 pm

    You give the nutritional values per serving which is great but nowhere did I see how many servings this made! Can you leave it in the reply? Thanks

    Reply
    • seekinggoodeats

      August 23, 2020 at 10:16 pm

      Hello! 6 servings 🙂 Enjoy! I love this casserole in fact I added it to my menu this week! LOL!

      Reply
4.75 from 12 votes (12 ratings without comment)

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Image of Kori Butler Seeking Good Eats Founder

Hey there, I'm Kori.

I’m a culinary school trained chef specializing in holistic nutrition and wellness. I’ve always been a major foodie, and as I’ve aged, the full impact of my love of food—and not-necessarily-healthy eating habits—caught up to me. In an effort to make positive changes in my life (and hopefully yours, too), I created this website where I could share great-tasting, craveable, healthy recipes.

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