Is Tuna Keto? An Essential Guide to Including Fish in Your Low-Carb Diet

October 5, 2025 •

3 min read

With nearly zero carbohydrates per serving, tuna is an ideal protein source for those following the ketogenic diet. This versatile and affordable fish can easily fit into a low-carb eating plan, providing essential nutrients while helping you stay in ketosis.

Quick Summary

This article explores tuna's excellent nutritional profile, its role in a keto lifestyle, and the best ways to prepare it. It also compares fresh versus canned varieties and offers practical tips for safe consumption and recipe creation.

Key Points

Naturally Low-Carb: Tuna contains virtually zero carbohydrates, making it a perfect protein source for the keto diet.
High-Protein Powerhouse: This lean fish is an excellent source of protein, helping to maintain muscle mass and increase satiety on a keto plan.
Omega-3 Rich: Tuna is packed with heart-healthy omega-3 fatty acids, which provide numerous health benefits beyond simple weight management.
Canned is Convenient: Both water-packed and oil-packed canned tuna are keto-friendly, with the latter offering more fat macros, which can be useful for hitting dietary goals.
Versatile Ingredient: Tuna can be easily incorporated into a variety of low-carb meals, including salads, melts, and patties, by substituting high-carb components.
Mindful of Mercury: Consume tuna in moderation, particularly larger species like albacore, to mitigate concerns about mercury levels.

The Case for Tuna on a Keto Diet

Tuna is a powerhouse of lean protein with virtually no carbohydrates, making it a natural fit for the ketogenic diet's strict macronutrient requirements. This saltwater fish, available fresh or canned, provides a wealth of essential nutrients that support overall health while keeping your carb count low. Its adaptability allows it to be incorporated into a wide variety of meals, from simple salads to more elaborate dishes.

Nutritional Breakdown and Keto Compatibility

For a keto diet, the primary concern is the carbohydrate count, and tuna is an exceptional choice. Both fresh and canned varieties contain virtually zero carbs, meaning they will not disrupt the state of ketosis. Beyond its favorable macronutrient ratio, tuna is rich in several key micronutrients vital for those on a low-carb regimen. It is an excellent source of omega-3 fatty acids, which are beneficial for heart and brain health. Other important nutrients include vitamin B12, selenium, and vitamin D, all of which contribute to immune function, energy levels, and bone health.

Canned vs. Fresh Tuna: A Keto Comparison

The most accessible form of tuna is canned, but the way it's packed can influence its fat and calorie content. Canned tuna is available packed in either water or oil, and both are keto-friendly, though with different nutritional profiles. Fresh tuna, such as ahi or yellowfin, is also an excellent option and is typically leaner.

Practical Considerations

While canned tuna is highly convenient and shelf-stable, fresh tuna can be an excellent choice for a low-carb meal if you have access to it. It offers a more robust flavor and texture. When using canned tuna, the choice between water-packed and oil-packed depends on your dietary goals. Water-packed is lower in calories and fat, while oil-packed (especially if using a healthy oil like extra virgin olive oil) provides additional fat macros needed for keto. Always be mindful of any added ingredients in flavored pouches or brands, as they can sometimes contain unexpected carbs.

Comparison Table: Canned Tuna Varieties (Per 1-oz serving)


Nutrient	Fresh Tuna (Yellowfin)	Canned Tuna (Water-Packed)	Canned Tuna (Oil-Packed)
Calories	91.8	24	56
Protein	19.87g	6g	8g
Fat	0.81g	<1g	2g
Carbohydrates	0g	0g	0g
Omega-3s	~500-700mg	Varies (up to 56mg DHA)	Varies (up to 29mg DHA)
Sodium	31.45mg	70mg	118mg

Creative and Delicious Keto Tuna Recipes

With tuna's neutral flavor profile and high protein content, it serves as a fantastic base for numerous keto meals. By swapping high-carb additions like bread or crackers with low-carb alternatives, you can create satisfying and compliant dishes.

Recipe Inspiration for Keto Tuna Meals

Keto Tuna Salad: Mix canned tuna with full-fat mayonnaise, chopped celery, and a dash of Dijon mustard. Serve it in a lettuce cup, bell pepper half, or on cucumber slices.
Tuna Melts (without the bread): Create savory tuna patties with cheese, egg, and tuna. Bake or pan-fry them for a warm, comforting dish.
Stuffed Avocado: Mash tuna with keto-friendly mayonnaise and seasoning, then spoon the mixture into the hollows of a halved avocado.
Tuna Cakes: Form drained tuna into patties with almond flour and egg, then pan-fry until golden brown.
Spicy Tuna Cucumber Bites: Combine canned tuna with spicy mayonnaise or sriracha and serve on rounds of cucumber for a quick and fresh snack.

Considerations for Tuna Consumption on Keto

While tuna is very beneficial, it's important to consume it in moderation due to potential mercury levels, particularly in larger species like albacore. Most health organizations recommend limiting canned tuna to a few times per week. To learn more about mercury in seafood, consider visiting the FDA's official recommendations for detailed guidance on safe consumption.

Conclusion

Is tuna keto? The answer is a definitive yes. As a zero-carb, high-protein food packed with healthy fats and essential nutrients, tuna is an excellent dietary component for anyone on a ketogenic diet. By choosing the right type and being mindful of preparation, you can enjoy this affordable and versatile ingredient while staying in ketosis and reaping its numerous health benefits. From quick salads to hearty melts, the possibilities for keto-friendly tuna meals are vast and delicious.

Frequently Asked Questions

Yes, canned tuna is an excellent choice for a keto diet. Both water-packed and oil-packed varieties contain almost no carbs and are a great source of protein and fat, respectively.

Absolutely. Fresh tuna, like canned, contains no carbohydrates and is a fantastic high-protein addition to your ketogenic diet. It can be grilled, seared, or baked.

No, canned tuna in oil remains very low in carbs. The oil simply adds healthy fat to the meal, which is a key component of the keto diet. For a boost in fat content, choose tuna packed in a keto-friendly oil like olive oil.

Tuna offers high-quality protein for muscle support, omega-3 fatty acids for heart and brain health, and essential vitamins like B12 and D. It's a low-calorie yet satisfying option for weight management.

To make a keto tuna salad, simply mix drained canned tuna with full-fat mayonnaise, finely chopped celery, and your choice of spices like salt, pepper, or dill relish. Serve it in lettuce wraps, bell peppers, or on avocado halves instead of bread.

Mercury exposure can be a concern with frequent fish consumption. Canned light tuna from smaller fish generally has lower mercury levels than canned albacore or fresh tuna. As with any seafood, moderation is key for safe consumption.

You should always check the nutritional label on flavored tuna pouches. While many are low in carbs, some contain added sugars or starchy fillers that can increase the carbohydrate count, potentially interfering with ketosis.