What is the Lowest Carb Seafood for a Healthy Diet?

December 10, 2025 •

3 min read

According to the USDA, many types of finfish and shellfish contain virtually zero carbohydrates per serving, making them excellent choices for low-carb lifestyles. But what is the lowest carb seafood specifically, and which options are best for a ketogenic diet? From finfish like cod to crustaceans like shrimp, understanding the carb counts helps you build a healthier plate.

Quick Summary

Many types of finfish and shellfish, including salmon, cod, tuna, shrimp, and crab, contain zero or near-zero carbs, making them a cornerstone of low-carb and ketogenic diets.

Key Points

Zero-Carb Finfish: Many common fish like cod, salmon, and tuna contain 0g of carbohydrates per serving.
Lowest Carb Shellfish: Crustaceans like shrimp, crab, and lobster are virtually carb-free, making them ideal for strict low-carb diets.
Variable Shellfish Carbs: Shellfish like oysters and mussels contain a small amount of carbohydrates that should be accounted for on a strict ketogenic diet.
Preparation is Key: To maintain a low carb count, avoid breaded or battered seafood and use simple cooking methods like baking or grilling.
Nutrient-Dense Protein: Beyond low carbs, seafood provides high-quality protein, essential omega-3 fatty acids, and key vitamins and minerals.
Avoid Hidden Carbs: Watch out for imitation crab meat and pre-made sauces, which can contain hidden sugars and starches.

Understanding Carbohydrates in Seafood

When it comes to low-carb eating, seafood is a standout protein source. The vast majority of finfish and many types of shellfish contain little to no carbohydrates naturally. The nutritional profile typically consists of high-quality protein, healthy fats (especially omega-3s in fatty fish), and essential vitamins and minerals. However, it's crucial to understand that the final carb count depends heavily on preparation. Breaded, battered, or sweetened seafood preparations can add significant carbs, completely changing the nutritional outcome.

Zero-Carb Finfish: The Top Choices

For those seeking the absolute lowest carb options, many finfish are the answer. Both lean and fatty fish offer a perfect zero-carb profile per 100g serving when prepared simply.

Cod: A lean white fish with a mild flavor, cod contains 0g of carbohydrates and is an excellent source of protein.
Salmon: A fatty fish rich in omega-3s, salmon is also naturally carb-free. Both wild and farmed varieties are suitable.
Tuna: Whether fresh yellowfin or canned, tuna offers 0g carbs and is packed with protein and omega-3s.
Mackerel: A high-fat, high-omega-3 fish with a more intense flavor. It is completely carb-free.
Halibut: A lean white fish, raw halibut contains 0g of carbohydrates and 20g of protein per 100g.

Lowest Carb Shellfish: Careful Selection

Most shellfish are also very low in carbohydrates, though it's important to be mindful of certain varieties that contain slightly more. For a true zero-carb experience, crustaceans are the way to go.

Shrimp: One of the most popular and versatile low-carb seafood options, shrimp contains 0g of carbs per serving.
Lobster: A rich and decadent choice, lobster meat is also carb-free and packed with protein.
Crab: Similar to lobster, crab meat contains 0g of carbohydrates when prepared plain.
Scallops: These have a very low carb count, but not zero. Per 100g, steamed scallops contain about 3g of carbs.
Oysters: These tend to have a slightly higher carb count than other shellfish. A dozen medium oysters can contain around 7g of carbs.
Mussels: Steamed mussels contain about 6g of carbs per serving, making them suitable in moderation.

Finfish vs. Shellfish: A Carb Comparison


Seafood Type	Approx. Carbs (per 100g)	Notes
Cod	0g	Lean white fish, excellent protein source.
Salmon	0g	Fatty fish, high in omega-3s.
Tuna	0g	Canned or fresh, rich in omega-3s.
Shrimp	0g	Versatile crustacean, low calorie.
Crab	0g	Rich, flavorful crustacean.
Scallops	3g	Very low carb, but not zero.
Mussels	6g	Suitable in moderation, contains carbs.
Oysters	5-7g	Highest carb count of the common shellfish.

The Importance of Preparation

To maintain the low-carb integrity of your seafood, simple cooking methods are best. Frying in high-carb coatings like flour or breadcrumbs will quickly add unwanted carbohydrates. For example, a recipe for crispy fried shrimp using almond flour and keto breadcrumbs offers a low-carb alternative to traditional breading. Sticking to methods that use healthy fats and natural seasonings is key.

Low-Carb Cooking Methods

Grilling: Seasoned fish fillets or skewered shrimp and scallops can be grilled for a smoky, carb-free meal.
Baking: Place fish fillets or lobster tails in the oven with a little olive oil, lemon, and herbs.
Steaming: Steaming shellfish like mussels, clams, or prawns is a gentle method that requires no added carbs.
Sautéing: Pan-fry shrimp or scallops in butter or olive oil with garlic and herbs for a quick, flavorful dish.

What to Avoid on a Low-Carb Seafood Diet

While most seafood is low-carb, it’s important to be aware of items that are not. Imitation crab meat, often found in California rolls or seafood salads, contains added starches and is not keto-friendly. Similarly, be cautious of pre-marinated seafood or restaurant dishes, which may contain hidden sugars or high-carb ingredients in their sauces. Always opt for plain, fresh, or frozen seafood and prepare it yourself to ensure it remains low-carb.

Conclusion: Embracing a Low-Carb Seafood Lifestyle

For those on a low-carb or ketogenic diet, seafood represents a fantastic and nutritious choice. While a wide variety of finfish like cod, tuna, and salmon are virtually carb-free, shellfish require slightly more attention due to varying carbohydrate levels. By opting for simple, clean preparations—such as grilling, steaming, or baking with healthy fats and seasonings—you can maximize the health benefits and keep your carb count low. With countless delicious and simple recipes available, incorporating low-carb seafood into your weekly meal plan is both easy and rewarding. For more information on general keto-friendly foods, Healthline provides an excellent resource.

Frequently Asked Questions

Most finfish, including cod, tuna, salmon, and mackerel, contain virtually zero carbohydrates per 100g serving, making them excellent low-carb options.

Yes, most shellfish are keto-friendly. Shrimp, crab, and lobster contain no carbs, while scallops, mussels, and oysters have a small amount that should be factored into your daily total.

Yes, fatty fish such as salmon and mackerel have zero carbohydrates despite their higher fat and omega-3 content, making them excellent choices for low-carb and keto diets.

You should avoid seafood that is breaded, battered, or prepared with sugary sauces. Imitation crab meat should also be avoided due to added starches.

Yes, plain canned tuna, typically packed in water or oil, contains no carbohydrates and is a convenient low-carb protein source.

Yes, oysters have some carbohydrates. A 100g serving of oysters can have around 5g of carbs, so they should be consumed in moderation on a strict keto diet.

Simple cooking methods are best. Try grilling, baking, steaming, or pan-frying with healthy fats like olive oil or butter and seasoning with herbs and spices instead of high-carb breading or sauces.