Can I eat canned tuna on keto? A Complete Guide to Including Tuna in Your Ketogenic Diet

November 5, 2025 •

4 min read

Did you know a standard serving of canned light tuna packed in water contains less than 1 gram of carbs and is an excellent source of protein? The low-carbohydrate, high-protein profile of canned tuna makes it a convenient and affordable staple for those asking: 'Can I eat canned tuna on keto?' This guide will help you navigate the best choices to ensure it aligns perfectly with your dietary goals.

Quick Summary

Canned tuna is a high-protein, low-carb food suitable for the ketogenic diet, but mindful selection is crucial. Factors like the liquid it's packed in, mercury levels, and potential additives should be considered to maintain nutritional integrity.

Key Points

Canned tuna is keto-friendly and low in carbs, making it a versatile staple for the ketogenic diet.
Choose canned light tuna (skipjack) over albacore to minimize mercury exposure, especially with frequent consumption.
Opt for tuna packed in water or extra virgin olive oil and avoid inflammatory seed oils often used in cheaper varieties.
Always read the label for hidden carbs in flavored tuna products, which can contain added sugars or fillers.
Incorporate canned tuna into diverse keto recipes, such as salads, patties, and stuffed vegetables, to add variety and nutrients to your diet.
Consume tuna in moderation (typically 2-3 times per week for light tuna) to keep protein intake balanced and manage mercury risk.

The Nutritional Powerhouse of Canned Tuna

For those on a keto diet, finding convenient, high-protein, and low-carb options is essential. Canned tuna fits this description perfectly, offering a versatile and budget-friendly meal component. At its core, plain canned tuna contains virtually no carbohydrates, making it a safe choice for maintaining ketosis.

Beyond its macronutrient profile, tuna is packed with valuable micronutrients. It is a fantastic source of omega-3 fatty acids, which are critical for cognitive function and reducing inflammation. A serving also provides an excellent dose of selenium, a powerful antioxidant that supports immune function, and vitamin D, essential for bone health. This makes canned tuna not just keto-compliant, but a genuinely healthful addition to your diet.

Water-Packed vs. Oil-Packed: A Keto Comparison

The choice between tuna packed in water and tuna packed in oil is one of the most common dilemmas for keto dieters. While both are low-carb, their fat and calorie content differs significantly, influencing your overall daily macros.

Which Option is Right for Your Ketogenic Goals?

Tuna Packed in Water: This version is leaner and lower in calories. It retains more of its natural omega-3 fatty acids, as they are not lost when draining the liquid, unlike with oil-packed varieties. However, for those needing to increase fat intake to meet ketogenic ratios, you will need to add healthy fats separately, such as mayonnaise or avocado oil.
Tuna Packed in Oil: This option provides additional fat and calories, which can be beneficial for keto dieters seeking higher fat content. The key is to choose tuna packed in a healthy oil, such as extra virgin olive oil, and to avoid varieties packed in inflammatory oils like soybean or vegetable oil. Some keto followers even utilize the flavorful, high-fat oil from the can for salad dressings.


Feature	Water-Packed Canned Tuna	Oil-Packed Canned Tuna
Fat Content	Very low	Higher, depending on the oil
Omega-3s	Retains more natural omega-3s upon draining	Some omega-3s may be lost when draining
Calorie Count	Lower	Higher
Benefit for Keto	Excellent for protein macros; requires added fat for optimal ratios	Helps meet higher fat macro targets and adds flavor
Considerations	Add healthy fat sources like avocado or keto mayo	Choose a high-quality oil (e.g., extra virgin olive oil); avoid inflammatory oils

Important Considerations for Regular Canned Tuna Consumption

While canned tuna is a keto asset, it's not without some important health considerations, primarily mercury content and potential additives.

Mercury Levels and Species Selection

All tuna contains some level of mercury, a heavy metal that can be harmful in high amounts. The amount varies by species and size. Smaller species, like skipjack (often labeled as 'canned light tuna'), have significantly lower mercury content than larger species, such as albacore.

The FDA recommends limiting albacore tuna intake to no more than once per week, while canned light tuna can be consumed more frequently, up to two to three servings (8 to 12 ounces) per week for most adults. Moderation and choosing the right species are key to mitigating this risk. For further information on mercury levels in different types of fish, you can consult a reliable source such as the FDA's mercury levels in commercial fish and shellfish page.

Hidden Carbs and Additives

Always check the nutrition label, especially on flavored or pre-mixed tuna products. Some manufacturers add sugar, starches, or other ingredients to enhance flavor or texture, which can increase the carbohydrate count. Stick to plain tuna packed in water or extra virgin olive oil to be safe. Some brands even sneak in high-carb ingredients like pea fiber. Simple is always best on keto.

Protein Intake and Ketosis

For some people, consuming too much protein can trigger gluconeogenesis, where the body converts excess protein into glucose, potentially hindering ketosis. While tuna is a high-protein source, this process is not typically a concern for those with normal protein consumption. Most keto dieters can comfortably consume moderate amounts of tuna as part of a balanced diet without issue.

Delicious Keto-Friendly Canned Tuna Recipes

Classic Tuna Salad (Low Carb): Mix canned tuna (drained) with high-fat mayonnaise, chopped celery, and a dash of Dijon mustard. Serve it in a lettuce wrap, bell pepper halves, or on cucumber slices instead of bread.
Keto Tuna Cakes: Combine tuna with a binder like a large egg and a low-carb flour alternative such as almond flour. Form into patties and pan-fry in avocado oil until golden brown.
Tuna Stuffed Avocados: Halve an avocado and scoop out some of the flesh. Mix the flesh with tuna, keto mayo, and seasonings, then spoon the mixture back into the avocado shell.
Creamy Tuna Casserole (Keto): Create a hearty casserole by mixing tuna with shredded cabbage or cauliflower rice, heavy cream, and shredded cheese. Top with crushed pork rinds for a crunchy topping before baking.

Choosing the Best Canned Tuna on Your Keto Journey

When at the store, prioritize these factors to make the best choice for your keto needs:

Species: Opt for smaller species like skipjack (canned light tuna) due to lower mercury levels.
Packaging Liquid: Choose water-packed for a leaner, lower-calorie option, or pick a high-quality oil-packed variety (extra virgin olive oil) for added healthy fats.
Ingredients: Check the label carefully for added sugars, starches, or inflammatory oils.
Sourcing: Consider sustainably sourced options to support responsible fishing practices.

Conclusion

In short, canned tuna is an excellent, keto-friendly food that provides a cost-effective source of high-quality protein and beneficial nutrients like omega-3 fatty acids, selenium, and vitamin D. To maximize its benefits and minimize risks, make informed choices about the species of tuna, whether it's packed in water or a healthy oil, and read labels to avoid hidden carbs. By following these guidelines, you can confidently include canned tuna in a variety of satisfying, low-carb meals.

Frequently Asked Questions

Not all canned tuna is suitable. While plain tuna packed in water or high-quality oil is fine, you must read labels on flavored or pre-mixed products. These often contain added sugars, starches, or inflammatory oils that can be detrimental to ketosis.

Both can work, but for different purposes. Tuna in water is leaner and lower in calories, ideal if you are adding fats from other sources. Tuna packed in a high-quality oil like extra virgin olive oil offers more fat and calories, helping you reach your fat macro goals.

Due to mercury content, moderation is recommended. The FDA suggests that adults can safely eat two to three servings (8-12 ounces) of canned light tuna (skipjack) per week. Albacore tuna, which has higher mercury, should be limited to about 6 ounces per week.

To reduce mercury risk, choose smaller species like skipjack (canned light tuna) over larger albacore. Limit your weekly intake, follow FDA guidelines, and diversify your protein sources with other low-mercury fish.

For most individuals on a keto diet, moderate consumption of tuna will not cause an issue. However, consuming very high amounts of protein can stimulate gluconeogenesis, where the body converts excess protein into glucose. Stick to moderate portions to be safe.

Instead of bread, serve your tuna salad in lettuce cups, bell pepper halves, celery sticks, or atop cucumber slices. You can also mix it with avocado to make a creamy, fat-rich filling for avocados.

Yes, canned tuna is a good source of omega-3 fatty acids, which are highly beneficial on a ketogenic diet. Omega-3s help reduce inflammation and support cognitive function, complementing the low-carb lifestyle.