The first time it dawned on me that tuna fish might be the greatest weight-loss food ever was about 30 years ago when I first started working as a floor trainer at the Equinox Fitness Club in New York. There was a bodybuilder there who was trying to get in “contest” shape for an upcoming event, and during the two weeks leading up to the contest, I saw the tiny bit of remaining fat he had on his muscular frame virtually disappear. I asked him what he was eating. “Tuna and vegetables,” was the answer.
This was in 1990, when no one was talking about keto diets—everyone was still on high-carb/low-fat eating plans. So the “tuna and vegetables” prescription was heresy. But—at least in this one case—it was truly working.
Later, when I experimented on myself with different foods at different times during my workout regimens, I found that a meal based around a simple can of tuna fish—particularly if it wasn’t swimming in pasta or accompanied by potatoes—was always energizing. Only years later, when I became a nutritionist, did I find out that tuna is rich in tyrosine, a precursor of the “alert” neurotransmitter, dopamine, which is why it can wake you up and get you energized.
Tuna: Health Benefits
Because tuna is such a ubiquitous food, we tend to take it for granted. But it’s one of the best sources of high-quality protein we have, and it’s available to just about anyone, even in areas where healthy food isn’t easy to come by.
Though tuna doesn’t have as much omega-3 fat as salmon or sardines, it’s still considered a fatty fish, and a serving of tuna provides some healthy omega-3s, as long as it comes from a reliable source. Canned tuna from big commercial companies typically has fewer than half a gram of omega-3 fat. It’s better than nothing, but you wouldn’t write home about it.
The nutrient content of tuna differs greatly depending on the company that canned it, the type of tuna (Atlantic, Pacific, white, light, skipjack), and how it’s packed (water or oil). We recommend the kind packed in extra virgin olive oil. Even so, all tuna is a terrific source of protein, containing large amounts of all the essential amino acids and then some. A single can of light tuna packed in water provides an astonishing 42 grams of high-quality protein for less than 200 calories.
That same can also contains more than 100 percent of the Daily Value for niacin, 29 percent of vitamin B6, and 82 percent of vitamin B12.
Tuna is also a superb source of the cancer-protective and immune-supporting trace mineral selenium. That can of light tuna provides almost 200 percent of the Daily Value. So even if you use one can for two portions, you’re still getting almost 100 percent of the Daily value of this vital nutrient.
What About Mercury?
The mercury issue is a serious one, but not nearly as serious as you might think. Yes, mercury is a neurotoxin, but the primary danger is to pregnant women. Many papers have been written weighing the potential damage to healthy adults taking in small amounts of trace mercury against the benefits you’d lose by avoiding tuna. These analyses generally come to the same conclusion: the enormous health benefits of fish (and tuna) far outweigh any real harm.