Can you eat tuna in oil on keto?

December 4, 2025 •

4 min read

According to the USDA, a 5-ounce can of tuna in oil contains 280 calories, with zero carbohydrates. The answer to whether you can eat tuna in oil on keto is a definite yes, but with key distinctions to understand between oil and water-packed varieties, and important health considerations like mercury content.

Quick Summary

Tuna in oil is a valuable, high-fat protein source for the ketogenic diet. Critical factors include choosing the right type of oil, monitoring mercury intake, and checking for hidden carbs in flavored products. It is important to drain or use the right oil and consume in moderation.

Key Points

Yes, but choose wisely: Tuna in oil is keto-friendly due to its high protein and fat content, but the type of oil and species of tuna are important factors.
Prioritize healthy fats: Opt for brands packed in healthy oils like extra virgin olive oil instead of less desirable seed or vegetable oils.
Manage mercury intake: Limit your consumption, especially of higher-mercury albacore tuna, and choose low-mercury skipjack or light tuna for more frequent meals.
Check for hidden carbs: While plain canned tuna is carb-free, always read the nutrition label on flavored tuna products to avoid added sugars and fillers.
Portion control is key: Eat tuna in moderation, alongside other food sources, to manage both mercury exposure and total calorie intake.
Benefits beyond fat: Tuna also provides heart-healthy omega-3 fatty acids, protein, and nutrients like selenium and vitamin D.
Texture and flavor: Canned tuna in oil offers a richer, softer texture and flavor profile that can enhance your keto dishes.

Understanding the Nutritional Difference

When comparing canned tuna, the primary difference for a keto dieter is the packing medium: oil or water. While the fish itself is a lean protein source, the oil is where the fat content, crucial for ketosis, is concentrated. For example, a 5-ounce can of tuna in oil can have significantly more calories and fat than the same portion packed in water. The oil infuses into the tuna, softening its texture and boosting its fat and calorie count, which can be highly beneficial for meeting your daily fat macros on a ketogenic diet.

Choosing the Right Oil

Not all oils are created equal, especially on a keto diet. The best choice is often tuna packed in extra virgin olive oil (EVOO). EVOO is a healthy, monounsaturated fat that complements the ketogenic lifestyle. Many conventional brands, however, use cheaper vegetable or seed oils, such as soybean or canola oil, which are high in omega-6 fatty acids. While omega-6s are not inherently bad, a high intake can disrupt the optimal omega-3 to omega-6 ratio, which is not ideal for managing inflammation. Always check the ingredients list to confirm the type of oil used in your canned tuna.

Tuna in Oil vs. Tuna in Water: A Comparative View

To clarify the nutritional differences, let's compare canned tuna packed in oil versus water.


Feature	Tuna Packed in Oil	Tuna Packed in Water
Fat Content	Significantly higher fat, crucial for keto macros.	Very low fat, less ideal for hitting high-fat goals.
Calorie Count	Higher calorie content, helpful for energy on keto.	Lower calorie count, better for low-calorie diets.
Protein	High protein content, similar to water-packed.	High protein content, similar to oil-packed.
Texture	Softer, moister texture from the infused oil.	Firmer, drier texture.
Flavor	Richer, more pronounced flavor.	Lighter, more neutral flavor.
Omega-3s	May be higher depending on the fish species.	High in DHA, an important omega-3, but overall content may be lower.

Navigating Mercury and Additives

While tuna is an excellent keto food, it is important to be mindful of its mercury content. As a larger predatory fish, tuna can accumulate higher levels of methylmercury. The amount varies by species and size:

Albacore ('white') tuna: Typically contains higher mercury levels. Due to this, health experts, including Consumer Reports, recommend limiting its consumption, especially for vulnerable groups like pregnant women.
Skipjack ('light') tuna: Generally a smaller, faster-growing species with significantly lower mercury levels, making it a safer option for more frequent consumption.

To balance health benefits with mercury risk, most health organizations suggest consuming fish, including light tuna, 2-3 times per week and limiting higher-mercury species.

Checking for Hidden Carbs

Plain canned tuna, whether in oil or water, contains virtually no carbohydrates. However, flavored tuna packets and certain ready-to-eat products can contain added sugars, starches, or other fillers that increase the carb count. Always read the nutrition label carefully. Look for simple ingredients: tuna, oil, water, and salt. Avoid products with ingredients you can't pronounce or that are clearly non-keto.

Delicious Keto Recipes with Tuna in Oil

Incorporating tuna in oil into your keto meal plan is easy and can add a satisfying richness to your dishes. Here are a few ideas:

Keto Tuna Salad: Mix drained tuna in oil with homemade avocado-based mayonnaise, diced celery, red onion, and herbs. Serve in lettuce wraps or alongside cucumber slices.
Tuna Stuffed Avocado: Combine tuna salad with creamy avocado and stuff it back into the avocado halves for a quick, high-fat meal.
Tuna Melt Cups: Mix tuna in oil with a little mayo and cheese, and bake in a muffin tin until golden. These are perfect for portion control.
Tuna Patties: Create patties from tuna, almond flour, an egg, and some spices. Fry in avocado oil until crispy for a delicious entree.

For more culinary inspiration, consider browsing resources like Dr. Berg's Keto Tuna Recipes.

Conclusion: The Final Verdict on Tuna in Oil

For those on a ketogenic diet, canned tuna in oil is a keto-friendly food that provides a convenient and affordable source of protein and healthy fats. The crucial distinction lies in choosing varieties packed in quality oils like extra virgin olive oil and being selective about the species of tuna. By opting for low-mercury options like skipjack or light tuna and keeping consumption in moderation, you can enjoy the delicious flavor and nutritional benefits of tuna in oil while staying safely in ketosis. Always prioritize reading labels to avoid unwanted carbs and seed oils, making tuna a valuable staple in your low-carb pantry.

Frequently Asked Questions

Tuna packed in oil is often preferred for keto as it contains significantly more fat and calories, which helps meet the high-fat requirements of the diet. However, you should choose a product packed in healthy oil like extra virgin olive oil.

Due to mercury content, it is best to eat tuna in moderation. Health authorities recommend most adults eat 2-3 servings of light or skipjack tuna per week, and less frequently for albacore tuna.

Skipjack or canned light tuna generally contains the lowest levels of mercury, making it the safer choice for regular consumption.

You can eat some flavored tuna packets on keto, but it's crucial to check the nutrition label. Some contain added sugars or fillers that increase the carb count, while others are keto-friendly.

Draining the oil removes much of the added fat, but the tuna itself remains a zero-carb, high-protein source. To maximize fat intake for keto, you may choose to use some of the oil in your recipe.

Look for brands that explicitly state they use extra virgin olive oil (EVOO). Brands like Genova and Jego offer keto-friendly options packed in quality oil.

Since tuna is naturally lean, packing it in oil, especially healthy olive oil, significantly increases its fat content. This makes it an easy way to boost your fat intake without adding significant carbs.