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August 21 2019

The Definitive Guide To Fish: Why and How To Eat It

By Mark Sisson
43 Comments

In nutrition, there are very few universal consensuses. Conventional wisdom says that fat makes you fat and whole grains are essential, and millions of people agree, but the ancestral health and keto communities (and reality) disagree. Primal and keto folks don’t worry much about saturated fat and limit polyunsaturated fat; conventional health advocates do the opposite. The opinion on meat intake varies wildly, with some people suggesting we eat nothing but red meat, others recommending “palm-sized” pieces of strictly white meat, and still others cautioning against any meat at all. Pick a food and you can find a sizable group that hates it and a sizable one that loves it. You can find researchers who spend their lives making the case against it and researchers who spend their lives making the case for it.

But not fish. Fish is about as close to a universal as any food. Barring the vegans and vegetarians (some of whom, however, are sneaking wild salmon when their followers aren’t watching), everyone appreciates and extols the virtues of eating seafood. Including me.

Sea Food = Sea Change: The Evolutionary Story

Remember: I always view things through an evolutionary prism. It’s where I begin. If something doesn’t make sense in the light of evolution, it probably doesn’t make sense at all. And seafood has been one of the most important dietary factors in human brain development. Without the selenium, iodine, zinc, iron, copper, and DHA found abundantly in fish and shellfish, human brain encephalization—the massive increase in relative size and complexity of the brain representing a shift toward higher order thought—wouldn’t have been easy to pull off. Maybe impossible.

If the human brain came to rely on the nutrients found in seafood for its evolution, it stands to reason that they remain important. The studies bear this out. Fish offers unique and important benefits to humans living today.

Not to mention the imbalanced, inflammatory omega-3:omega-6 ratios most of us have, or had. Even if you’ve been Primal for ten years, you spent a good portion of your life eating the standard Western diet full of industrial seed oils high in omega-6 fatty acids. Omega-3s from seafood help correct that balance.

The Modern Picture: Calm the Alarm

But there’s a problem, isn’t there? If you listen to the alarmists, our seas are overfished and full of toxins, and the fish that remain are dripping with mercury, cadmium, and other heavy metals. Farmed fish are even worse, some say; they swim in tepid baths of antibiotics, soybean oil, and glyphosate. Besides, oceanic acidification is killing all the delicious fish and shellfish and crustaceans. Pretty soon the only thing served at Red Lobster will be fried jellyfish.

Though there are glimmers of truth to all those claims, they’re certainly exaggerated:

  • There are still plenty of excellent and sustainable seafood choices to make, according to Seafood Watch, which takes environmental impacts, overfishing, and other ecological and safety concerns into account.
  • While some species are indeed overburdened with heavy metal contamination, plenty aren’t. Eat salmon, sardines, mackerel, younger, smaller tuna. Besides, most seafood—in one study, this included shrimp, crabs, squid, and tropical fish in the Atlantic Ocean—is high enough in selenium that it binds to and prevents absorption of mercury.
  • Jellies may be taking over, or they may be following the natural 20-year boom and bust cycle observed throughout history.
  • Even farmed salmon isn’t as bad as we might assume. And farmed mollusks—oysters, clams, mussels—are as good as wild, since they live no differently from their wild cousins.

Even if all those claims were totally on the level, we’re faced with a grand overarching truth: You have to eat something. What, are you gonna eat vegan meat patties instead of cod, salmon, sardines, and oysters? Drink Soylent? Go vegan? Go Breatharian?

Of course not. You need to eat seafood. You know you should.

But isn’t it too expensive?

For one thing, I already mentioned that safe farmed fish exists. Farmed salmon probably isn’t as bad as we’ve been led to believe (or assume), as long as you watch out for the egregious ones. U.S.-farmed trout, barramundi, and catfish show up with very low toxin levels and good nutrient profiles. And farmed bivalves like oysters, clams, and mussels are raised like they’re wild. There’s basically no difference between a farmed oyster and a wild oyster. They both live out in the ocean attached to rocks, munching on what the sea provides.

Two, wild seafood isn’t always expensive.

Restaurant supply shops, Walmart, and other large stores often have frozen wild salmon, cod, and other wild fish for cheap, about $5-6 per pound.

At Costco, you can get wild caught salmon (at least on the West coast) in season for $5-6 pound. You might have to buy it whole, though (recipe down below). They also have other types of wild fish for good prices.

Canned seafood is a viable option.

Fish and Seafood: How To Optimize the Benefits

Why We Need Seafood

First, evolutionary precedent, which I already discussed. It’s folly to ignore the long history of humans eating seafood. It’s higher folly to ignore the importance of seafood in human brain evolution. Wherever they have access, people eat seafood.

Second, the benefits are well-established. Even if the links to better health are purely correlational (and they’re not, since we have controlled trials listed above), seafood looks great on paper: bioavailable protein, high levels of essential nutrients, the best source of long chained omega-3 fatty acids.

Third, seafood is a reliable source of important micronutrients that may be lacking on a terrestrial Primal, keto, or carnivore diet. Selenium, magnesium, folate, astaxanthin, and vitamin E can be tough to get if you’re just eating steaks and ground beef.

A recent study on the ketogenic Mediterranean diet had great results feeding its participants over two pounds of fish per day. Two. Pounds. Mostly salmon, sardines, and mackerel, which are fatty omega-3 rich fish very low in contaminants.

But what about those who say they’re meat eaters, turf people who claim grass-fed beef and pastured pork is enough for them? Fish is meat. Fish are animals. You’re seriously limiting your options—and selling your ancestors short—by willfully avoiding seafood. And you’re probably missing out on some important nutrients. Like iodine, for example, which doesn’t show up in the standard nutritional databases but is incredibly important for brain and thyroid health and almost certainly appears most abundantly in seafood.

What Exactly Should I Eat?

Okay,  so should I just throw in some salmon and be on my way?

Salmon is a great start, but there’s way more fish (and bivalves, crustaceans, and cephalopods) in the sea.

Can’t I just take fish oil? As a fish oil purveyor, I wish I could say that fish oil is enough. It offers incredible benefits not to be dismissed, but it’s not equivalent to food either. The fact is, I do both. Seafood contains a ton more than just the omega-3s. Just check it out….

  • Salmon: Vitamin D3, B-vitamins, magnesium, iron, selenium.
  • Cod: B-vitamins, magnesium, selenium, potassium
  • Halibut: B-vitamins, vitamin D3, magnesium, selenium, potassium
  • Sardines (canned): B-vitamins, vitamin D3, selenium, calcium (if bone-in), iron, copper
  • Scallops: Vitamin B12, magnesium, folate, selenium, zinc.
  • Oysters: B-vitamins, magnesium, selenium, zinc, copper, iron, omega-3s, manganese
  • Mussels: B-vitamins, selenium, zinc, manganese, folate, omega-3s
  • Clams: Vitamin B12, iron, magnesium, vitamin A
  • Shrimp: B-vitamins, magnesium, selenium, zinc, astaxanthin (a potent carotenoid, great for ocular and mental health)
  • Crab: B-vitamins, vitamin E, magnesium, folate, selenium, zinc, copper
  • Lobster: B-vitamins, vitamin E, selenium
  • Squid: B-vitamins, magnesium, iron, copper, zinc, selenium, vitamin E
  • Octopus: B-vitamins, magnesium, iron, copper, zinc, selenium

Although I didn’t mention it, every single sea creature you can eat is a very good source of highly bioavailable protein and, usually, creatine.

And some studies even suggest that fish proteins themselves offer unique benefits.

Most of the research is in animals, but it’s compelling and another good—if speculative—reason to include fish in your diet.

I’m Sold. How Much Should I Eat?

Keeping in mind the contamination in certain varieties, eat much as you can afford/tolerate. It’s hard to eat too much seafood. In my experience, there seems to be a built-in regulatory mechanism that reduces the palatability of seafood at a certain level of consumption. A big slab of wild sockeye salmon is fantastic, but I can’t eat pounds of it like I can with a grass-fed ribeye.

You can also use omega-3:omega-6 ratio as an indicator. Run the numbers on the seafood you’re eating and aim for a 1:1 or 1:2 ratio and you should be golden.

In my opinion, leaner fish has no upper limit. Eat as you desire.

Keep in mind that the keto Mediterranean diet study I recently discussed gave over 2 pounds of fish to participants every day, and they had great results. Two. Pounds. Mostly salmon, sardines, and mackerel, which are fatty omega-3 rich fish very low in contaminants. After 12 weeks of that:

  • They lost 30+ pounds.
  • Their BMIs dropped from almost 37 to 31.5, from the middle of class 2 obesity to the bottom of class 1 obesity.
  • They lost 16 centimeters, or 6 inches, from their waist.
  • Fasting blood sugar dropped from 118 (pre-diabetic) to 91 (ideal).
  • Triglycerides dropped from 224 to 109.
  • HDL increased from 44 to 58.
  • They went from prehypertensive to normotensive.
  • Their liver enzymes and liver fat reduced and in some cases completely resolved.
  • All 22 subjects started the study with metabolic syndrome and ended it without metabolic syndrome.

As always, pay attention to how you feel. Eat and observe. Make it an official N=1 experiment and look for the feedback it provides.

How I Do Seafood

Okay, but how do you eat it? How do you prepare it?

Admittedly, there’s a lot less room for error with seafood.  It goes bad more quickly, cooks faster, and simply isn’t as forgiving. We’ve all had the experience of buying some salmon fresh from the butcher, keeping it in your fridge a half day too long because we weren’t sure how to prepare it, and having to throw it out. That’s the worst.

I’m not a big “recipe” guy (I have people who help me parse out my creations into legible formats for blog posts and cookbooks). I like to improvise. A dish here, a dash there. So, I’m just going to give a freeform account of how I eat fish, shellfish, and other seafood. If you need clarification on something, feel free to ask in the comment board.

I like doing a kind of pseudo-ceviche using any high quality lean fish—halibut’s great—marinated in Primal Kitchen® Greek Dressing & Marinade with a few splashes of tamari or soy sauce and some diced fresno chile. Let it sit for 5-10 minutes, then plow into it. Really good, even though if you tried to serve this in Peru they’d probably arrest you.

I always have canned sardines from Wild Planet in my pantry. A favorite quick (and keto-friendly) meal is to do a can or two of sardines mashed up with an avocado and a tablespoon or two of Greek Goddess dressing.

If I’m doing salmon, I’ll sometimes marinate the fish in the Primal Kitchen No-Soy Teriyaki.

Another great way to cook fish is in a curry. Sear the fish, making sure to get crispy skin if it’s on. Set aside. In the same pan without washing or draining, heat up some garlic, ginger, chili peppers (if you like it hot), and onions (or shallots), adding more fat if you need it. Salt. When they’ve softened, add the curry powder or paste. Cook for a minute or so. Then add some bone broth and coconut milk. Reduce until you’ve reached the texture you desire. I’ll keep gelatin powder on hand to whisk in if it doesn’t have enough body. At the last moment, add the fish back in and toss to coat.

Scallops? Either raw at a good sushi joint, preferably separated by thinly sliced lemon, or seared in butter followed by a pan reduction with white wine and butter. By the way, for those who are interested, Butcher Box has some killer scallops now (it’s literally the last day to grab the deal—apologies to anyone reading this tomorrow.) And full disclosure—I’ve always been a proud affiliate. They do things right there.

Clam chowder is still the best way to eat clams, roasted on an open fire on the beach with a little sand still in there. Maybe it’s just the New England in me.

Anytime I’m out at a decent restaurant I trust with oysters on the menu, I order them. At least a half dozen, raw. I also like the canned smoked oysters from Crown Prince.

Mussels I like the classic way: cooked in butter, white wine, and garlic. Only modification I make is after the mussels have cooked, I remove them from the pan, sprinkle in some gelatin powder, and reduce down to make a viscous sauce.

Cod or other similar lean white fishes are best in lots of butter and garlic, followed by a squeeze of lemon.

Whole salmon? Clean, gut, and scale. If you can, keep the liver. It’s delicious. Salt and pepper the interior and exterior of the salmon. Cut some deep vertical slashes in the outside, on both sides. Stuff shallots, garlic, and lemon slices into the interior and inside the slashes. Coat with avocado oil, then grill over indirect heat with the cover on until skin is crispy and flesh is lightly pink and flaky, or bake at 375 for 30-40 minutes.

If I’m ever cooking a cephalopod, it’s all about the Instant Pot. Throw some bone broth, lemon juice, and olive oil in the pot with the squid or octopus and cook on manual for 15-20 minutes. If you like, you can take it out, allow it to cool, then grill it over coals or open flame. Save the broth.

Whenever I cook fish, I use either monounsaturated fats (as found in avocado oil and olive oil) or saturated fats (as found in butter and coconut oil). Both types of fats enhance absorption of omega-3 fatty acids, whereas omega-6 fats inhibit it. Both omega-3 and omega-6 compete for the same absorption pathway.

When applicable (as in curry), I also use turmeric to cook my fish. Turmeric and its curcumin enhances absorption of omega-3s, specifically increasing DHA levels in the brain.

I know seafood is intimidating for some people. They don’t like the “fishiness.” They don’t know how to cook it. It’s “too expensive.” It goes bad too quickly. Hopefully, after today you feel a bit better about cooking and eating seafood. Hopefully, you feel equipped and empowered to incorporate some salmon, cod, trout, oysters, and other marine animals into your diet.

Take care, everyone, and please leave your favorite ways to eat seafood down below. How much seafood do you eat? What’s your go-to recipe? What underrated sea animal do you covet but others do not?

Thanks for reading!

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43 thoughts on “The Definitive Guide To Fish: Why and How To Eat It”

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  1. This article is wonderful and eases a lotnof the anxieties I have had about seafood. Thank you for the very timely and relevant information. One question… my local stores only carry canned oysters packed in cottonseed oil. Is that a healthy oil? Thank you.

  2. Great article, but now mention about Sushi? It has a bad rap out there.

  3. Break an egg into a 2-cup microwave-safe bowl. Lightly beat together with salt, pepper, and dill weed. Drain one can of salmon and stir flesh into egg mixture. Microwave on high 3 minutes. Edges will pull away from bowl but center will still be moist. Let sit until center firms up. Eat.

    1. Huh. Gotta try that, but in an oven. I’m not a big microwave lover. Thanks.

    1. Another vote for Vital Choice – one of the better (if not best) options for purchasing fish. Pricey, but worth it.

  4. Here on the island, we are lucky to be able to spear or catch fish and we love to cook it right over an open fire on the beach…we’ve also wrapped fish in banana leaves with a bunch of butter and herbs inside and then tied it all together like a package…like gifts from the sea! Goes great with a sunset and a gathering of your tribe haha!

    1. Yum! I’m on the opposite coast from you and we do something similar here 🙂

  5. We love fish and eat it often. Thanks for these ideas. What do you suggest for family member with allergy to seafood? How can she best get Omega-3s? Thanks!

  6. Farmed fish is the equivalent of CAFOs. I would not call fish living in a toxic cesspool ‘not as bad as we might assume’. It is definitely not good for the environment; other sea life or the sea in general; and especially human consumption. I have witnessed these fish farms. You couldn’t pay me to eat it.

  7. I just purchased some West Coast Dover Sole. I’ll look for some good recipes for that. Stuffed Sole is great (gluten/free). Also, I do occasionally like fish lightly tossed in cassava flour and egg, and then fried in coconut oil (or avocado oil). There’s just something about battered fish that is delightful. Battered can be made with gluten-free beer, also. Served with fresh lemon. I know this doesn’t meet Keto but probably qualifies for Paleo cooking. Stuffed flounder is another favorite with spinach or artichokes. Parmesan encrusted fish is another real treat or macadamia nut encrusted.

  8. I eat fish everyday in my Big Ass Salad. Salmon/Sardines/Kippered Herring/ Tuna and Smoked TJ’s Oysters. Always rotate them. Once in awhile I’ll have some shrimp or clam chowder. I’m gettin’ enough. Love calamari, but it’s hard to find.

    1. How do you do your sardine salad? Do you buy whole or boneless skinless? I just tried my usual salad salmon mix with whole sardines instead of salmon and the taste was so terribly strong I couldn’t eat it. Would love to eat sardines whole again but have lost the taste.

      1. Try the Wild Planet sardines in marinara sauce, sitting on top of a Big Ass Salad. It’s like restaurant food.

          1. you’ve never been to a good restaurant then walter 😉

      2. I use Trader Joes Smoked sardines for Caesar Salad

        In a large bowl drain the olive oil from the can and set fish aside. Add juice from half a lemon, a heaping tablespoon of primal mayo and some fresh cracked pepper. Whisk together then toss in the romaine lettuce. Sometimes I break up the sardines and toss them together sometime I serve topped with one sardine. Its great without the parma cheese but I like it traditional.

  9. Mark,
    Great article. I usually take some chlorella when I eat high mercury fish. Will that provide adequate protection fro the heavy metals?

    1. Chlorella is definitely protective against mercury in fish, as well as other toxins. I take it everyday, but esp. with fish to help detoxify …

  10. Mark,

    There are reports that ocean plastics will soon reach 1/3 of the mass of ocean fish, and exceed it by 2050. What do we know, really know, about the effects of seafood plastic consumption?

    1. A recent study (in Michigan, I think) says plastics go right through you, and the same goes for any other creature. In other words, it’s probably okay, for now. Your body has no use for it and lets it go. I suppose if concentrations get higher it could interfere by masquerading as food to creatures that eat tiny stuff.

  11. I jumped at the cheap price of the wild Alaskan frozen salmon at walmart before, came in a huge bag and I was amazed at the price. Got home and realized it had an additive in it, I think it was sodium tripolyphopshate or some other scary additive. Couldn’t give that to my salmon loving toddler… On a positive note, the other day, Earth Fare had wild Alaskan fresh slabs of salmon on sale for 6.99/lb, cheapest I’ve ever heard, so for the first time in my life I ate non-canned, non-frozen fish! It was delicious. I just baked it with olive oil, salt, and pepper. I’d eat a ton of it if I could afford to buy it this way, or even frozen.

    1. Earth Fare is great for deals on seasonal seafood. Lobster tails just went on sale for $5 each at mine along with $5 filet mignon.

  12. The amount of plastics being dumped into the oceans and how they are working into the food chain is a concern.

    “I’d like to share a revelation I’ve had during my time here. It came to me when I tried to classify your species. I realized that you’re not actually mammals. Every mammal on this planet instinctively develops a natural equilibrium with their surrounding environment, but you humans do not. You move to another area, and you multiply, and you multiply, until every natural resource is consumed. The only way you can survive is to spread to another area. There is another organism on this planet that follows the same pattern. Do you know what it is? A virus. Human beings are a disease, a cancer of this planet. You are a plague, and we are the cure.” – Agent Smith

  13. You didn’t mention sashimi, it’s not everyone’s bag but some fish is so good it’s best raw. Salmon, tuna, mackerel, and bream make fabulous sashimi (or ceviche) and scallop sashimi is unbelievable. I simply never eat this fish cooked if I can help it. They taste better raw and there’s less washing up!

  14. Hi,
    I love that you went really deep in this very important topic. I am the opposite to many primal followers. My main source of protein is 85% fish however, I was looking forward to read the article to find out more information about the quantity of fish I should eat in order to meet a good protein intake of protein. I am scared sometimes fish does not meet with the full intake of protein.

    Also, I just want to mention that I am a bit afraid about your recommendation to eat salmon as many consumers do not do the task fully.
    Salmon is a species in danger of extinction. Moreover, as there is an excess in the consumption of salmon, other species such as bears are also in danger of extinction since they are fully dependent of only salmon.
    I believe we can leave the salmon a bit out (besides worries about contamination) – what about the other animals in the planet besides the humans that also deserve to consume these species?

  15. Breatharian! I got two laughs out of that one. First when I thought you made it up, and second when I found out that you didn’t!

  16. I use Carlson’s Wild Norwegian Cod Liver Oil daily. Is this better than a typical fish oil supplement?

  17. I eat carnivore off and on, but I do include fish: shrimp, salmon, raw oysters, squid, and Wild planet sardines, smoked oysters on occasion. Oh and fresh whitefish. All great. I do feel those exploring carnivore would add a lot to their diet to add fish (despite those all beef types). The Inuit did fine on fish and whale blubber for a very long time. It’s nice to hear Mark give us permission to eat more than wild Atlantic salmon. If you are interested in my journey with carnivore/keto, check out my website. I am a 64 year old woman and starting to get quite fit. lekimball.com

  18. Love Wild Planet Sardines. Costco (bless them) sells the tins in a six-pack. My favorite way to eat sardines is to take Mark’s suggestion up a notch: I get freshly made guacamole and pico de gallo. I like my guac spicy, so I season accordingly. I make sure the pico and sardines are seasoned, too. I place my guac and pico in a nice salad bowl, with the sardines on top. Delish!!

  19. I hate to break it to you, Mark, but even when DH was bringing in a comfortable middle-class salary in the Midwest $5-6/lb was “special occasion” territory. (We’ve since moved to the South Pacific, where the pay isn’t as good but fish can sometimes be had for less than chicken.)

  20. Adore this Mark! Thank you 🙂

    As a basically pescatarian this has been a wonderful insight. I find it too difficult or just a bit heavy digesting meat often, but I live for seafood!

    Quick follow up question- anything I could be missing not eating meat, dairy or eggs and just seafood? If so how best can I combat those issues?

    Cheers,

    Lola

  21. What is your opinion of Tilapia? I notice you didn’t mention it. Personally I’ve steered clear of it because it doesn’t exist in the wild, only farmed, but I didn’t realize farmed fin fish of USA origin is ok-I’ve just always stayed clear.

  22. Love seafood!

    Honestly can’t get enough. Thrive off it. Love all the offcuts like fins, collars and heads too. Great for soup of course as well!

    One thing I covet but seems like it is considered a throw away fish down here is blue grenadier- do you know it Mark? It’s about the cheapest fish I can get in Melbourne Australia and I can’t figure out why! Any insights?

    Also- how bad are basa fillets in Aus? They too are cheap and look great.. but I’m wary after hearing bad reports. Your insight would be awesome if you have time ?

  23. You forgot soups. For me, I love my seafood either raw, or in a Thai-like coconut lemongrass soup, with or without some curry paste in it.

  24. Thank you for this information Mark. A question- what do you think about the impact of the chemicals used in canning when you eat canned salmon, oysters, tuna, sardines, etc.? Does the benefit of the nutrition al profile of the seafood outweigh the possible detrimental effects of the chemicals used to coat the can?
    Thank you!
    Denise

  25. Any white fish is delicious broiled topped with sour cream or a sour cream like concoction probably such as yogurt. Simple, easy, delicious! Experiment, it’s fun!

    To Laura: Cottonseed oil is lousy, heavily processed, full of mono and polyunsaturated fats, and possibly loads of pesticides since cotton is not regulated as a food source. My opinion of course but based on reading plenty about it. It’s done bad things to me a good friend when eaten in the past. It’s on my ‘avoid’ list up there with ‘aspartame’ (Equal).

  26. I am wondering about the high levels of TMAO in fish in regards to its correlation with heart disease. Are you concerned about this? I just saw a new study come out about low carb paleo diets causing high levels of TMAO in the blood (which is correlated with heart disease). Sarah Ballantyne had a great post on this study and wondered if you saw it yet.

  27. My favorite way to cook salmon is grill it oI n a plank. The fat doesn’t drip out and it comes out so juicy and delicious. I just marinate it in olive oil and salt and pepper, but you could add scallions, spice, or whatever you want.
    A second best is in the instant pot, up on the rack that comes with the instant pot. I pour a sauce of tamari, sesame oil, lime juice, salt, pepper, honey over it, and put ginger slices and water in the bottom. Especially good for wild, drier salmons.

  28. There is also the option of getting your own fish, if possible, and keeping in mind the “throwback” fish, such as sea robins (lots of flavor), skates, rays, and more. Hank Shaw talks about a lot of fish that most people throw back, but are quite edible.

    Also, opinion on Whole Foods farmed salmon? They convinced me it’s good, and it sure is delicious, but I’m still skeptical.

  29. Often overlooked is canned cod liver in it’s own juices. It delicious and nutritious by itself. And you eat eggs, you can mash it with a few boiled eggs. Also, stay clear of seafoods that comes from the Far East.