In theory, canned tuna is the essence of simplicity, a quick, easy way to get a protein- and-omega-3-fatty-acids hit, all in a handy, on-the-go package.

But then there’s the mercury to worry about. Are you getting poisoned with every flakey bite? And those omega-3s; is all tuna created equal when it comes to fatty acids? And what about the dolphins, turtles and other bycatch – not to mention overfishing of the tuna itself? Are we going to run out of tuna just so that I can make a healthy, easy casserole?

Oy! Suddenly, not so much with the simplicity!

But before you throw your tuna cans in the garbage can, let’s see if we can answer some of those questions.

First off, you should know that there are actually several different species that become canned tuna. If the label reads “white tuna,” it’s albacore. If it reads “light tuna,” it’s typically skipjack, but it might also be tongol, yellowfin (ahi), or bigeye. The upside of albacore is that it tends to have more omega-3 fatty acids, healthy unsaturated fats vital for growth, development, and brain function. They also help prevent heart disease. Unfortunately, albacore also has a higher concentration of mercury.

Whether the trade off is worth it is a matter of some debate, although authorities and activists alike agree that if you’re a young child, you’re nursing, you’re pregnant, or soon-to-be pregnant, it’s best to stick with light tuna and even then, limit intake given mercury can potentially cause issues with brain and nervous system development. The FDA recommends no more than 12 ounces a week. The Environment Defense Fund suggests 12 ounces a month. (Check out Environmental Working Group’s handy Tuna Calculator Guide.)

However, if you’re just an average Joe (or Josephine), the omega-3/mercury trade-off is worth it, so go for the albacore. Although, if you have a balanced diet, you don’t need that much protein, so 3 or 4 servings of fish, canned or other, is all you really need. Also keep in mind that packing tuna in oil leaches omega-3s, so always buy water-packed. Some foodies might complain that water-packing ruins the texture, but if you’re that much of a connoisseur, why are you eating canned food to begin with?

Finding a canned tuna that’s good for the environment is a little trickier. A few years ago, there was a huge backlash over dolphin bycatch in the tuna fishing. The industry bent over backwards to save Flipper and trumpeted it loudly, but that didn’t do much for the turtles, sharks, and seabirds meeting grizzly fates via tuna longlines, a practice in which one central line drags scores of other baited lines, catching everything in its path. Your best bet to avoid all this karma-zapping gore is to seek out fish caught using troll or pole-and-line gear, which are both much more discriminating in what they catch.

As for the fish populations themselves, tuna are fast-growing and they reproduce young, so they’re generally a responsible fish to eat. Albacore stocks in the US and British Columbia are particularly strong, so you don’t need to worry about overfishing. Skipjack also has a robust population the world over, so you’re doing the right thing eating that too. If you’d like to dig deeper into the environmental aspects of tuna fishing, the Monterey Bay Aquarium Seafood Watch website is a great resource.

Where not to look, however, are the major canned tuna brands websites. They may waffle on about sustainable fisheries and the fancy foundations they’re all forming, but it’s all smoke and mirrors. For example, according to HealthyTuna.com, a site set up by Starkist, Bumblebee, and Chicken of the Sea, the three companies “have committed $100,000 per year to protect sea turtles in the long-line tuna fishery.” 100k, huh? Nice work, you contributed your CEO’s dry-cleaning bill to a vaguely beneficial cause. I bought a box of Girl Scout cookies this year. Does that put me in line for the Congressional Medal of Honor? When you’re willing to list where and how your fish was caught in plain English on your label, then we’ll talk.

Conversely, smaller brands are often more forthcoming with this type of information on their label, albeit they’re also more expensive – but what’s a clear conscience worth?

About our Guest Contributor – Formerly “weight challenged,” Denis Faye dropped 50 pounds following a 5-year jaunt through Australia, a trip that helped him become the extreme sports and fitness enthusiast he is today. He’s been a professional journalist for 20 years, writing for Outside, the New York Times, the Los Angeles Times, Los Angeles Magazine, Wired, Men’s Health, Men’s Journal, GQ, Surfer, and Pacific Longboarder, specializing in fitness, nutrition and weight loss articles. His sports include swimming, scuba, rock climbing, spelunking, mountain biking, trekking, and—most importantly—surfing. Denis currently writes for Beachbody, which provides effective and popular home fitness programs.