Tuna boasts a reputation as a health food, and for good reason; it's loaded with essential nutrients that boost your overall health and well-being. It's also good for weight loss, thanks to its high protein content and relatively low calorie count. Serve your tuna with low-cal and low-fat mix-ins to promote weight loss, and choose low-mercury varieties of tuna as your healthiest option.
Always consult a medical professional before starting a new diet, and see a nutritionist or registered dietitian for help planning your diet regimen.
Calories in Tuna Can Fit Your Diet
As long as you choose the right kind, tuna is a moderate source of calories, which makes it appropriate to include in a weight loss diet. Your best bets are tuna steak, or tuna canned in water. A 3-ounce portion of tuna steak, cooked over dry heat, is 112 calories, while a half-filet is 203 calories. And 3 ounces of light tuna, packed in water, is just 72 calories -- or 142 calories per can.
Tuna canned in oil is a higher-calorie option. While some types of tuna are packed in heart-healthy oils, like olive oil, they can be harder to fit into a calorie-controlled diet due to this higher calorie content. A 3-ounce serving of tuna canned in oil is 168 calories, and a can will set you back 339 calories.
If you're currently eating a can of tuna canned in oil twice per week, switching to tuna canned in water will help you lose more than 5 pounds in a year, even without making other diet changes (339 - 142 -- 197 cals saved x 2 x 52 weeks -- 20,488 cals saved, divide by 3,500 to get 5.85 lbs).
Tuna's Protein Helps You Lose Weight
Tuna is a great weight loss food thanks to its high protein content. In addition to providing amino acids that your body can use to build muscle tissue -- a process that boosts your metabolism -- protein helps with weight loss because of its high thermic effect. Protein is hard to digest, and its high thermic effect means that your body burns more calories in breaking down protein than it does breaking down carbohydrates and fats, so eating more protein-packed foods boosts your overall calorie burn. A study published in the American Journal of Clinical Nutrition found that people who boosted their protein intake from 15 to 30 percent of their daily calorie intake felt more satisfied and full and dropped weight and body fat.
Eating 3 ounces of tuna steak boosts your protein intake by 24 grams, while 3 ounces of tuna canned in water offers 17 grams of protein. That's a significant amount toward your daily protein needs -- 56 and 46 grams for men and women, respectively.
Tuna Has Other Good-For-You Nutrients
Tuna also comes packed with other essential nutrients, which help keep you healthy while you lose weight. For example, a 3-ounce serving of tuna in water offers 36 percent of the daily value for vitamin B-12 -- a nutrient that aids in oxygen transport, which is essential for supporting an active lifestyle. Tuna is also high in phosphorus -- a mineral found in your cell membranes and DNA -- and selenium, an antioxidant mineral that protects your tissues from damage. Just one serving of canned tuna provides 86 percent of your daily selenium needs. Tuna also contains a small amount of omega-3 fatty acids, which are specialized fats that boost heart health and support brain function.
Recipe and Serving Choices Can Be Important
While tuna itself is good for weight loss, not every dish featuring tuna is slimming. For example, tuna salad made with lots of mayonnaise can add hundreds of calories, along with unhealthy fats abundant in mayo. Instead, make tuna salad with nonfat cottage cheese or plain, nonfat Greek yogurt. These mix-ins will add creamy texture with little fat, and they're also high in beneficial protein. Or add chunks of canned or grilled tuna to a spinach or kale salad, or top your tuna steak with a healthy pineapple-mango salsa.
Keep your mercury intake in check by choosing chunk light tuna, recommends Harvard Medical School. It's lower in mercury than other varieties, like white tuna, so it offers a safer and more healthful option. Overall, limit your intake of light tuna to no more than two 6-ounce portions weekly, recommends the New York City Department of Health and Hygiene.