Protein in Tuna: Canned vs Fresh, by Species, and Mercury Safety Guide

The quick answer: A 3 oz (85g) serving of canned tuna in water (drained) contains approximately 25g of protein with only 100 calories and under 1g of fat. This makes canned tuna one of the most protein-dense, affordable, and shelf-stable foods available — a staple in the diets of athletes, bodybuilders, and budget-conscious meal preppers worldwide.

How Much Protein Is in Tuna?

Tuna is an exceptionally lean fish with one of the highest protein concentrations of any food. Here is the protein content by common serving sizes for canned light tuna in water:

At 4.0 calories per gram of protein, canned tuna in water rivals shrimp for the best protein-to-calorie ratio among whole foods. A single 5 oz can delivers 42g of protein — more than enough for a full meal — at a fraction of the cost of fresh fish.

Canned Tuna: In Water vs In Oil

The packing medium makes a significant difference:

Draining the oil removes some but not all of it — tuna absorbs oil during canning. Even after thorough draining, oil-packed tuna has about 7g more fat and 68 more calories per serving than water-packed. For pure protein efficiency, water-packed and drained is the clear winner.

However, oil-packed tuna has its advantages:

• Richer flavor and more moist texture
• Better for salads and pasta where you want a silkier mouthfeel
• Slightly more omega-3 retention (some omega-3s leach into water and are lost when draining)

Fresh vs Canned Tuna

Fresh tuna steaks are a different experience entirely:

Fresh tuna steaks are slightly higher in protein per 3.5 oz because there is no water or oil displacement. Bluefin tuna is the fattiest and most expensive variety, prized for sushi, while yellowfin is the leanest fresh option.

Protein by Tuna Species

Different tuna species have distinct nutritional profiles:

Skipjack (labeled as "chunk light" in cans) is the most affordable, lowest in mercury, and still very high in protein. It is the best choice for regular consumption.

Mercury Considerations

Mercury is the primary health concern with tuna consumption. Here is what you need to know:

Practical guidelines:

• Light canned tuna (skipjack): Safe to eat 2-3 times per week for most adults
• White canned tuna (albacore): Limit to 1 serving per week
• Pregnant women: FDA recommends 2-3 servings of low-mercury fish per week; choose light tuna over albacore
• Children: Smaller portions, same frequency guidelines as pregnant women

Mercury accumulates in the body over time and is cleared slowly (half-life of about 70 days). If you eat tuna multiple times per week, sticking to skipjack/light tuna significantly reduces your mercury exposure.

Tuna as Budget Protein

Canned tuna is one of the cheapest protein sources available — and the cheapest shelf-stable one:

Store-brand canned tuna at roughly 2.4 cents per gram of protein is competitive with chicken breast and is the cheapest animal protein you can store in your pantry without refrigeration. A case of 12 cans (~$12) provides about 500g of protein.

Tuna Meal Prep Ideas

Canned tuna requires zero cooking, making it the fastest protein to add to any meal:

Classic Tuna Salad

Mix 1 can of tuna (42g protein) with 1 tbsp light mayo, diced celery, and lemon juice. Serve on whole wheat bread, in lettuce wraps, or over a green salad. Total protein: about 45g.

Tuna and White Bean Salad

Combine 1 can of drained tuna (42g) with 1/2 cup cannellini beans (8g), diced red onion, olive oil, and lemon. A Mediterranean-style meal with 50g protein.

Tuna Rice Bowl

Flake canned tuna over steamed rice with soy sauce, sesame oil, avocado, and cucumber. Quick, no-cook assembly for about 45g protein.

Tuna Melt

Top whole wheat toast with tuna salad and a slice of Swiss cheese (7.6g protein per oz). Broil until melted. About 50g protein per serving.

Seared Ahi Tuna (Fresh)

Season fresh yellowfin steaks with sesame seeds and sear for 1-2 minutes per side. Serve rare with soy-ginger dipping sauce. A 6 oz steak provides about 51g of protein.

Storage Notes

Omega-3 Content in Tuna

Tuna provides some omega-3 fatty acids, though less than fattier fish like salmon:

Canned albacore has significantly more omega-3s than light tuna, which is one reason some people prefer it despite the higher mercury. For comparison, salmon provides about 1,700mg per 3 oz — roughly 3x more than albacore tuna and 11x more than light canned tuna.

Frequently Asked Questions

Is canned tuna healthy?

Yes. Canned tuna is high in protein, low in fat, affordable, and shelf-stable. It is an excellent source of selenium, vitamin D, and B vitamins. The main consideration is mercury — stick to light (skipjack) tuna and limit albacore to once per week.

How many cans of tuna per week is safe?

For most adults, 2-3 cans of light (skipjack) tuna per week is safe according to FDA guidelines. For albacore (white) tuna, limit to 1 can per week due to higher mercury. Pregnant women and young children should follow the same frequency but with smaller portions.

Is tuna better than chicken for protein?

Per calorie, they are very comparable. Canned tuna in water has about 25g protein per 100 calories, while chicken breast has 31g per 165 calories (18.8g per 100 cal). Tuna is slightly more protein-efficient per calorie, but chicken breast provides more total protein per 3.5 oz serving. Chicken is more versatile in cooking, while tuna is more convenient (no cooking needed from a can).

Does draining tuna remove protein?

No. Draining removes only water or oil. The protein stays in the tuna meat. Always drain canned tuna thoroughly for the most accurate calorie count.

Is tuna good for building muscle?

Absolutely. Tuna is one of the leanest, most protein-dense foods available. Its high protein-to-calorie ratio makes it ideal for both muscle building (when combined with sufficient calories from other sources) and cutting (when minimizing calories while maintaining high protein).

Is pouch tuna better than canned?

Nutritionally, they are very similar. Pouch tuna tends to have slightly larger, more intact pieces (more like fresh tuna flakes), while canned tuna is more compressed. Some pouches have slightly lower sodium. Pouches are more portable but typically more expensive per ounce.

Can you eat tuna straight from the can?

Yes. Canned tuna is fully cooked during the canning process and is safe to eat directly from the can without any additional preparation.

What is the healthiest way to eat canned tuna?

Canned light tuna in water, drained, mixed with a small amount of olive oil or avocado (for healthy fats and omega-3 absorption), lemon juice, and vegetables. Avoid drowning it in mayo, which can double or triple the calorie count.

Track Your Tuna Intake and Stay Within Mercury Limits

Whether you eat tuna from a can, a pouch, or fresh from the fish counter, tracking helps you stay on top of both protein intake and weekly consumption frequency. Mealift logs every serving and keeps a running total of your daily protein, so you can hit your targets while keeping mercury-conscious variety in your diet.