Which is the least fatty fish? A complete guide to lean seafood

November 27, 2025 •

3 min read

According to USDA data, Atlantic cod contains as little as 0.7 grams of fat per 100-gram serving, making it one of the top contenders when asking which is the least fatty fish. While salmon and mackerel are celebrated for their omega-3 content, many people seek out the lowest-fat seafood for weight management or specific dietary needs. This guide delves into the leanest options, offering clear nutritional comparisons to help you make the best choice for your diet.

Quick Summary

This guide provides a comprehensive overview of the least fatty fish options, focusing on lean white fish like cod, haddock, and pollock. It examines their nutritional benefits, highlights key factors influencing fat content, and offers advice for healthy preparation methods. The article includes a detailed table comparing the fat, protein, and calorie content of various seafood types.

Key Points

Haddock is exceptionally lean: It is often cited as one of the least fatty fish, with a very low-calorie count.
Cod is a high-protein, low-fat choice: Atlantic cod contains less than a gram of fat per 100-gram serving and is rich in vitamin B12.
Pollock is versatile and lean: As a key source of high-quality, low-fat protein, it's used in fillets and processed products alike.
Flounder and sole are delicately lean: These flatfish offer a mild flavor and very low-fat content, perfect for careful preparation.
Choose moist cooking methods for lean fish: To prevent these fish from drying out, opt for baking, poaching, or steaming.
Combine lean fish with healthy sides: Pair low-fat fish with roasted vegetables or a fresh salad for a balanced, nutritious meal.

Identifying Lean vs. Fatty Fish

Fish can be broadly classified into two categories based on their fat content: lean and fatty. Fatty or oily fish, such as salmon, mackerel, and sardines, store a higher concentration of fat throughout their muscle tissue. This fat is rich in heart-healthy omega-3 fatty acids, but it also means a higher overall fat and calorie count.

In contrast, lean fish have a much lower fat content, with the majority of their fat stored in their liver rather than their flesh. These are typically white-fleshed fish and include well-known options like cod, haddock, and flounder. Their mild flavor and flaky texture make them incredibly versatile for cooking and a favorite for those aiming for a low-fat, high-protein diet.

The Contenders for Least Fatty Fish

Several fish species consistently rank as having the lowest fat content, making them ideal for health-conscious diners.

Haddock

Often cited as one of the leanest fish available, haddock is a white fish with a mild, slightly sweet flavor. A cooked 3-ounce serving of haddock contains a mere 0.5 grams of fat and is an excellent source of protein, with around 17 grams per serving. It also provides essential nutrients like selenium, phosphorus, and B vitamins.

Cod

Cod is another stellar example of a very lean fish. Pacific and Atlantic cod are both incredibly low in fat and calories, making them a popular choice for weight management. A typical 100-gram serving of Atlantic cod has less than one gram of fat. Its mild, flaky white meat is easy to cook and takes on the flavor of seasonings and sauces well. Cod is also a great source of vitamin B12.

Pollock

Alaskan pollock is a mild-flavored white fish that is a major source of lean protein. Its low-fat content and firm texture make it a key ingredient in products like imitation crab meat, but it is also excellent as a fillet. It provides high-quality protein with a minimal amount of fat.

Flounder and Sole

These flatfish are known for their delicate texture and very low-fat profile. A 3.5-ounce serving of flounder can have under 2 grams of fat, with less than 100 calories. Their mild flavor makes them a great entry point for those new to seafood.

Tilapia

For those who prefer a fish with a neutral, non-fishy taste, tilapia is a great option. It is a white fish that is low in fat and calories, providing a significant amount of protein. While its fat content is slightly higher than some other white fish, it is still an extremely lean choice.

Nutritional Comparison: Lean vs. Fatty Fish

To put the differences into perspective, here is a comparison of the nutritional values for a raw, 100-gram (3.5-ounce) serving of various fish, based on USDA data.


Fish Type (Raw, 100g)	Total Fat (g)	Protein (g)	Calories (kcal)
Haddock	0.6	20.0	87
Atlantic Cod	0.7	18.0	82
Whiting	0.7	20.0	132
Tilapia	1.5	19.0	129
Salmon (Atlantic, Wild)	6.3	20.0	142
Mackerel	16.0	18.0	-

Cooking Methods for Lean Fish

Because lean fish have so little fat, they can become dry if cooked improperly. It's crucial to use moist-heat cooking methods or add fat to keep them from drying out. Healthy cooking methods that preserve moisture include:

Baking: Wrap the fish in parchment paper or foil with some herbs and a splash of lemon juice to lock in moisture.
Poaching: Gently simmer the fish in water, broth, or wine until it becomes opaque and flakes easily.
Steaming: This method keeps the fish incredibly moist and highlights its delicate flavor.
Grilling or Sautéing: These can also be used, but require careful monitoring and potentially brushing the fish with a small amount of healthy oil to prevent sticking and drying.

Conclusion

When it comes to answering which is the least fatty fish, options like haddock, cod, and pollock consistently top the list. These lean white fish offer an abundance of high-quality protein and a minimal amount of fat, making them an excellent choice for a wide range of dietary needs, from weight management to general health. While fattier fish like salmon provide important omega-3s, lean fish can be enjoyed regularly as a low-calorie protein source. By understanding the nutritional differences and employing proper cooking techniques, you can enjoy these mild-flavored fish in many delicious and healthy ways.

For more detailed nutritional information on seafood, the official data from the USDA serves as an excellent resource. Visit the USDA FoodData Central here

Frequently Asked Questions

The primary difference lies in where they store their fat. Fatty fish like salmon store fat in their muscle tissue, which is why they are rich in omega-3s. Lean fish like cod store most of their fat in their liver, resulting in very low-fat content in their flesh.

No, lean fish are not less healthy. They offer different nutritional benefits. While they have lower levels of omega-3s compared to fatty fish, they are still excellent sources of high-quality protein and other essential vitamins and minerals, such as B12 and phosphorus.

For weight loss, haddock and cod are among the leanest options. Their high protein-to-calorie ratio helps with satiety, making you feel full for longer on fewer calories.

If you are looking for a low-fat substitute for salmon, a mild-flavored white fish like haddock or cod is a great option. Both offer similar flaky textures but with significantly less fat.

Yes, the cooking method can significantly affect the final fat content of a fish dish. Baking, poaching, or steaming fish adds little to no extra fat, whereas frying it in batter or a lot of oil will increase the fat content.

Tuna is considered a lean fish, especially when canned in water. However, its fat content can vary. For example, some fresh tuna (like certain yellowfin cuts) has higher fat than cod or haddock, but is still considered leaner than oily fish like salmon or mackerel.

Lean fish do contain some omega-3 fatty acids, but at much lower levels than oily fish. For significant omega-3 intake, fatty fish like salmon or sardines are better sources, or you can consider supplementation.