What 100g tuna usually contains

For raw yellowfin tuna, 100g typically provides about 109 calories, 24g protein, less than 1g fat, and zero carbs. Canned light tuna in water is similar, often landing around 110 to 120 calories with about 25 to 26g protein per 100g drained. Tuna packed in oil will usually have more calories and fat.

That protein-to-calorie ratio is the reason tuna is common in high-protein diets. It gives a lot of protein for a small serving, which can help with muscle repair, satiety, and easier macro tracking. If you use a meal photo app like Fitnit, tuna is also one of the simpler foods to estimate because the serving is usually easy to visually separate from rice, vegetables, or pasta.

How 100g tuna compares by type

Not all tuna is nutritionally identical. Skipjack and light tuna are generally smaller fish and often have lower mercury levels than albacore or bigeye tuna. Canned tuna can also vary in sodium depending on the brand and whether it’s packed in brine.

A practical rule: if you want fewer calories, choose tuna in water; if you want more calories for a meal, tuna in oil can make sense; if mercury matters most, choose lower-mercury varieties more often and rotate your seafood choices.

Health benefits and key nutrients

Beyond protein, tuna provides nutrients like selenium, vitamin B12, niacin, and some omega-3 fats. Those nutrients support normal metabolism, nerve function, and heart health. Tuna is not as omega-3-rich as salmon, but it can still contribute meaningfully to seafood intake.

Because tuna is so protein-heavy, it can be especially useful after training or as part of a higher-protein lunch. If your goal is muscle gain or fat loss, pairing 100g tuna with fiber-rich foods like beans, vegetables, or whole grains can improve fullness without adding many extra calories.

Mercury and safe intake

The main caution with tuna is mercury. Larger tuna species generally contain more mercury, so frequent intake of albacore, yellowfin, or bigeye should be balanced with lower-mercury fish choices. This matters most for pregnant people, children, and anyone eating fish often.

For most healthy adults, tuna can fit into a balanced diet, but variety is important. A sensible approach is to alternate tuna with salmon, sardines, trout, cod, shrimp, or other seafood so you can get the benefits of fish without relying on one species every week.

Tips

• If you want the leanest option, choose tuna canned in water and drain it well.
• Check the label for sodium, especially if you eat canned tuna often.
• Use tuna with vegetables or whole grains instead of mayo-heavy mixes if you’re watching calories.
• Rotate tuna with other seafood to reduce mercury exposure and improve nutrient variety.
• For home workouts, Fitnit can count reps automatically and help you stay consistent while you focus on nutrition and training.