The short answer: chicken usually wins by a little

For a lean, cooked comparison, skinless chicken breast typically edges out tuna in protein per 100 grams. USDA FoodData Central data generally puts roasted chicken breast around 31 grams of protein per 100 grams, while canned tuna in water is usually in the mid-20s per 100 grams. That means chicken is often the higher-protein choice, but not by a huge amount.

If you compare typical portions instead of 100 grams, the gap is still modest. A standard serving of either food can give you a lot of protein, which is why both are staples in high-protein meal plans.

Why the answer changes depending on the cut and preparation

Not all chicken and tuna are equal. Chicken breast has more protein than chicken thigh or breaded chicken. Tuna steaks, albacore, and some canned tuna varieties can get closer to chicken breast, while tuna packed in oil may have more calories without much extra protein.

Cooking method also matters because water and fat content change the weight of the food. Grilled, roasted, or baked lean cuts usually look best on a protein-per-calorie basis. If you’re using a meal photo tracker or logging by eye, portion size can matter as much as the food choice itself.

Which is better for your goal?

If your main goal is maximizing protein with very few calories, both are strong choices. Chicken breast often has a slight protein edge, while tuna can be just as convenient and very high in protein for the calories.

For muscle gain, fat loss, or simple meal prep, the bigger issue is consistency. A food that you’ll actually eat regularly is usually better than the mathematically perfect option. If you train at home, tools like Fitnit can help with rep counting and form checks so your protein intake lines up with your workout routine.

If you eat fish often, tuna also brings omega-3 fats, but it can come with mercury concerns depending on the type and how much you eat. Chicken does not have that issue.

Other factors: mercury, sodium, and overall health

Tuna is one of the fish people most often worry about for mercury, especially larger tuna species. Mayo Clinic and other health authorities recommend paying attention to fish type and serving frequency, particularly for pregnant people and children. Chicken does not have mercury concerns, so it can be the simpler everyday protein.

Canned tuna can also be high in sodium if it is not labeled low-sodium. Chicken can be very lean and lower in sodium when unseasoned, but packaged or deli chicken products may be heavily salted. In practice, the healthiest choice is usually the least processed version you can realistically prepare and enjoy.

Tips

• If you want the highest protein per calorie, choose skinless chicken breast or tuna packed in water.
• Compare servings by weight, not just by can or breast size, because portions vary a lot.
• Watch sodium on canned tuna and processed chicken products.
• Rotate protein sources during the week to reduce boredom and avoid relying too heavily on one food.
• If you eat tuna often, vary the species and serving frequency to keep mercury exposure lower.