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.
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.
- More omega-3s in your red blood cell membranes, less heart
- More omega-3s in your diet, lower expression of
inflammatory genes and less airway inflammation
if you have asthma.
- More EPA in your diet, improved
- More EPA and DHA in your diet, less progression
from inflammation into full-blown arthritis and improved rheumatoid
- More omega-3s in your diet, stronger anabolic
response to strength training.
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
- 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
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
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
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
What Exactly Should I Eat?
Okay, so should I just throw in some salmon and be on my
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,
- 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,
- Mussels: B-vitamins, selenium, zinc, manganese, folate,
- 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,
- Lobster: B-vitamins, vitamin E, selenium
- Squid: B-vitamins, magnesium, iron, copper, zinc, selenium,
- Octopus: B-vitamins, magnesium, iron, copper, zinc,
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.
- In one study, rats with
injured muscles saw faster recovery when fed cod protein as opposed
to casein or peanut protein.
- In people with insulin resistance, cod protein reduces
the inflammatory marker CRP and increases insulin
- Fish protein may even
enhance fat loss and
muscle gain compared to other protein sources.
Most of the research is in animals, but it’s compelling and
another good—if speculative—reason to include fish in your
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
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
- 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
- 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
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
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
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
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
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
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
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
Thanks for reading!
The post The
Definitive Guide To Fish: Why and How To Eat It appeared first
on Mark’s Daily