What Seafood Has the Lowest Carbs?

October 23, 2025 •

4 min read

According to the USDA, almost all types of fresh fish and lean shellfish contain virtually zero carbohydrates, making them an excellent choice for low-carb and ketogenic diets. However, some variations exist within shellfish, where certain types have small but notable carb counts, so knowing which seafood has the lowest carbs is key for strict diet adherence.

Quick Summary

The lowest-carb seafood includes most fin fish, such as salmon, tuna, cod, and mackerel, as well as many shellfish like shrimp, crab, and lobster. Differences in carbohydrate content are more pronounced among specific shellfish types, like clams and oysters, but remain minimal. The key is to consume fresh, unbreaded, or unfried preparations to avoid added carbs.

Key Points

Fin Fish are Carb-Free: Most fresh fish, including salmon, tuna, and cod, naturally contain virtually zero carbohydrates, making them ideal for strict low-carb diets.
Shellfish Have Minimal Carbs: While most shellfish like shrimp, crab, and lobster have negligible carb counts, some, such as mussels and oysters, contain a small amount of glycogen that registers as minimal carbs.
Preparation is Key: To keep seafood low-carb, avoid breaded, battered, or fried preparations, and be cautious of sugary sauces and glazes.
Omega-3 Benefits: Fatty fish like salmon and mackerel are not only low in carbs but are also rich in heart-healthy omega-3 fatty acids, offering extra nutritional value.
Versatile and Nutritious: Seafood is a great source of high-quality protein, vitamins, and minerals, and can be cooked in numerous low-carb ways, including grilling, baking, and steaming.

Your Guide to the Lowest-Carb Seafood Options

For those following a low-carb, keto, or a general health-conscious diet, seafood is a nutritional powerhouse. Not only is it rich in high-quality protein and essential omega-3 fatty acids, but most varieties are naturally very low in carbohydrates. This makes it a versatile and delicious choice for maintaining ketosis and overall wellness. While nearly all fish are carb-free, some shellfish contain minimal carbs, which is important for those tracking macros closely.

Fin Fish: The Zero-Carb Champions

When it comes to the lowest possible carbohydrate count, fin fish are the undisputed winners. With the exception of certain processed or prepared products, fresh fish contains no carbohydrates. This is because fish, like other animal proteins, does not store energy in the form of glycogen in its muscle tissue after being harvested.

Some of the best zero-carb fish options include:

Salmon: A fatty fish packed with heart-healthy omega-3s, protein, and vitamin D.
Tuna: Whether fresh or canned, tuna is an excellent source of protein with zero carbs.
Cod: A lean, mild-flavored white fish that is rich in B vitamins and provides a substantial amount of protein without any carbs.
Mackerel: A fattier fish loaded with omega-3s and other beneficial nutrients like selenium and potassium.
Trout: Another fantastic fatty fish option, versatile for grilling, baking, or pan-searing.
Sardines: These small, nutrient-dense fish can be eaten canned and are a powerhouse of omega-3s, protein, and calcium.
Halibut: A lean white fish with a firm texture and zero carbs.

Shellfish: Minimal Carbs to Keep in Mind

While most shellfish are also very low in carbohydrates, a few types contain small amounts of glycogen, which registers as carbs. For most low-carb dieters, these amounts are negligible, but for those on a very strict ketogenic diet, it is worth being mindful.

Here is a breakdown of common shellfish and their carb content:

Shrimp: One of the most popular shellfish, shrimp contains a negligible amount of carbs, with most cooked shrimp coming in at under 1 gram per 100g serving.
Crab: Whether king, snow, or dungeness, fresh crabmeat is extremely low in carbs, making it a perfect keto indulgence.
Lobster: A decadent, low-carb treat, lobster contains very few carbohydrates and is high in protein.
Mussels: While still low-carb, mussels contain a slightly higher amount of carbohydrates than some other shellfish, around 6 grams per 3-ounce serving.
Clams: These also have a slightly higher carb count than shrimp or crab, with one ounce containing around 0.89 grams of carbohydrates.
Oysters: Depending on the preparation, oysters can have a small carb count, typically around 5-7 grams per cup, which is important to remember for strict keto followers.

Comparison Table: Carbs in Popular Seafood (per 100g serving)


Seafood Type	Carbs (g)	Omega-3s	Protein (g)	Ideal For	Note
Wild Salmon	0.0	High	20+	Keto, Heart Health	Fatty fish, rich in nutrients
Tuna (Canned)	0.0	Medium	23+	Quick Meals	Versatile and convenient source of protein
Cod	0.0	Low	18+	Low-Calorie, Lean Protein	Mild-flavored white fish
Shrimp	<1.0	Low	24+	Versatile, High-Protein	Very low carb, quick cooking
Crab	<1.0	Low	17+	Special Occasion	Minimal carbs, delicate flavor
Lobster	<1.0	Low	17+	Gourmet Low-Carb	Very low carb, high in protein
Mussels	~6.0	Medium	20+	Nutrient Dense	Slightly higher carb count, but still low
Clams	~2.5	Medium	25+	Full of Minerals	Trace carbs, great source of iron

How to Keep Seafood Low-Carb

The preparation method is crucial for keeping your seafood meal truly low-carb. While the fish and shellfish themselves are low in carbs, the way they are cooked can add hidden sugars and starches. Here are some tips for carb-conscious preparation:

Avoid breading and battering: These coatings are often made with flour or breadcrumbs, which will add significant carbohydrates. Opt for grilled, baked, steamed, or pan-seared preparations instead.
Watch marinades and sauces: Many pre-made marinades, glazes, and sauces contain added sugar. Read labels carefully or make your own simple sauces with herbs, garlic, butter, and olive oil.
Use healthy fats: Cook your seafood in healthy fats like coconut oil, avocado oil, or butter to increase your fat intake on a keto diet.
Pair with low-carb vegetables: Serve your seafood with non-starchy vegetables like asparagus, broccoli, zucchini, or a fresh salad instead of potatoes or rice.

Conclusion

For anyone looking for low-carb protein options, seafood is a fantastic choice. The majority of fin fish are completely carb-free, while most shellfish contain only trace amounts. By choosing fresh, unprocessed options and being mindful of preparation methods, you can easily incorporate a wide variety of delicious and nutrient-rich seafood into your low-carb lifestyle. Fatty fish like salmon and mackerel offer the added benefit of healthy omega-3s, making them particularly valuable for overall health. Always remember to check preparation methods when dining out or buying pre-made products to ensure they haven't been prepared with carb-heavy ingredients like breading or sugary sauces.

Visit the Food and Agriculture Organization website to learn more about the nutritional value of fish and the utilization of dietary carbohydrates in aquatic animals.

Frequently Asked Questions

Most fresh fin fish, including wild salmon, tuna, cod, and mackerel, are naturally carb-free. As long as they are not prepared with sugary glazes or breading, they contain zero carbohydrates.

Yes, shrimp is a very low-carb seafood choice. Cooked shrimp contains less than 1 gram of carbohydrates per 100-gram serving, making it an excellent option for ketogenic and low-carb diets.

Yes, most shellfish are keto-friendly. Common choices like shrimp, crab, and lobster have negligible carb counts. You should, however, be mindful of options like mussels and oysters, which contain slightly higher but still minimal amounts of carbs.

The best methods are grilling, baking, steaming, or pan-searing. Avoid breading, flour-based batters, and commercially prepared sauces that might contain added sugars. Simple seasonings like lemon juice, garlic, herbs, and olive oil are best.

No, imitation crab meat is typically not low-carb. It is made from surimi, which is often mixed with starches and sugar, adding a significant amount of carbohydrates. It should be avoided on a strict low-carb or keto diet.

Canned tuna packed in water or oil usually contains zero carbohydrates. It is a great source of protein. Just be sure to check the label for any added ingredients, and avoid varieties packed in sauces.

Besides being low in carbs, seafood is packed with high-quality protein, essential vitamins (like B12), and minerals (like selenium). Fatty fish like salmon are also rich in omega-3 fatty acids, which support heart and brain health.