For today’s edition of Dear Mark, I’m answering a pair of questions from readers. The first one comes from the comment section of the excerpt from Paul Saladino’s new book : Can a seafood-only carnivore diet work? Will it miss anything? Is there anything to watch out for, add, or consider? The second one comes from the recent post about exercising during a fast . If someone’s trying to gain muscle, should they prioritize eating protein after a fast-breaking training session, or should they keep the fast going?
I have a question though. Is eating a seafood-only carnivore diet well rounded enough Mark? Will I cover all my bases nutritionally? I eat plenty of fish heads  (caught that post with interest) plus whole mollusks. Basically any seafood. What do you think? And how long term could this diet be?
It can definitely be done. You’ll have no issues hitting your recommended nutrient intakes, since seafood is one of the most nutrient-dense classes of foods around. But you’ll have to keep a few things in mind to do it right:
- You’ll want to avoid overloading on high-toxin fish. Don’t base your diet on shark, swordfish, king mackerel, and albacore tuna.
- You may run into problems getting enough fat. Because while you can certainly eat fatty seafood like king salmon and mackerel and get “enough” fat, you’d be overdosing on omega-3s.
Wait, what? Too many omega-3s? Aren’t those good for you?
Yes, but there’s a limit. I for one love sockeye salmon with crispy skin, but there’s definitely an “off-switch.” I can’t sit there and put down two or three pounds of it in a single sitting. And if I do eat a lot, I usually don’t want any more for at least a few days. This effect happens with other fatty fish, too, like mackerel. It doesn’t happen with leaner seafood, like cod. I’ll eat a huge amount of cod cooked in capers and butter and lemon. I’ll eat shrimp forever.
Most populations who ate significant amounts of seafood got most of their fat from terrestrial sources. Northern Europeans and people from the British Isles ate a lot of cold water fish, but they also ate huge amounts of dairy fat and animal fat (and other plant foods). The traditional Mediterranean diet wasn’t just sardines and anchovies, but also cheese and lamb and olive oil (and other plant foods). Pacific Island nations whose populations ate mostly seafood for their animal protein weren’t eating king salmon and fatty tuna; they were eating low-fat fish and getting a lot of their fat from coconut (plus fruit and tubers).
The only peoples we know who got a huge amount of dietary omega-3 from seafood and ate a close-to-carnivore diet were the Inuit, and even they also ate high-fat terrestrial animals or marine mammals with abundant fat stores.
Eating a high-fat diet with most of the fat coming from fatty fish is evolutionarily novel and, probably, unwise. And maybe impossible, or extremely expensive.
If you want to do seafood-based carnivore, try these:
- Incorporate leaner seafood (not just fatty fish) and branch out on your fat sources. Plus, it’s cheaper this way—wild salmon gets pricey.
- Eat white fish like cod, halibut, haddock. Excellent protein and mineral content with low absolute omega-3 levels.
- Eat sardines, salmon, mackerel—just not at every meal. Great protein and mineral content with high omega-3 levels.
- Eat bivalves and crustaceans like oysters, mussels, crab, shrimp, clams. Very high in micronutrients, plus you get the “eating the whole organism” effect.
- Use olive oil, butter, avocado oil, coconut oil for fat. Olives, avocados, and coconuts aren’t strictly carnivore, but their oils don’t contain any of the plant compounds that carnivores worry about—and butter is definitely carnivore-friendly, as it comes from an animal.
- Eat cheese, if you tolerate it.
- Eat egg yolks, if your seafood-centricity isn’t ideological.
- Figure out folate. Folate will be hard to come by. There’s just not a lot of folate in seafood. Then again, folate is hard to come by on standard carnivore diets, too, unless you’re eating liver every day—which probably isn’t a good idea.
What can you do?
1. You can source really, really good eggs. Joel Salatin claims to raise chickens  who lay eggs with 218 times the folate levels of normal eggs. That’s hard for me to believe, but I do know that chickens who eat lots of greens and other folate-rich foods will have more folate in their eggs than chickens who eat none. Another option is Eggland’s Best Organic Eggs, which have about 10% of your daily folate requirements in each egg (plus an impressive overall nutrient profile). Throw in a few of those each day and you’ll get a big boost.
2. You can eat some romaine lettuce. Hear me out. Romaine lettuce is actually a very good source of folate. Two cups of the stuff will give you a measly 1 gram of digestible glucose and over 30% of your daily folate requirement. Moreover, it’s very low in oxalates, the primary component in leafy greens that carnivores like to avoid.
I hope that helps. Let me know how it goes.
On the shorter fasts with fat loss AND muscle gain as the goal, would you recommend prioritizing protein intake following resistance training? I will typically lift weights in a fasted state first thing in the morning (4x week), and I’m wondering if I’m losing progress by prolonging my fast (and protein intake) until lunchtime.
Yes. Protein intake shortly after the workout is the best move for optimizing muscle protein synthesis and muscle gain. For fat loss, I’d also recommend doing some really light cardio after the training session before you eat to burn through the free fatty acids the exercise liberated from your body fat. By light, I mean light.
Go for a 20-minute walk around the block or on the treadmill.
Casually pedal the stationary bike.
Go for a hike.
Swim some laps.
Jog at a pace easy enough that you can hold a conversation.
I often prolong my fasts even after training because I’m not really interested in active muscle gain at this point. I’m mainly going for muscle maintenance, performance maintenance (train so I can play), longevity, and compression of morbidity. If I were to start a mass gain protocol, I would be eating lots of protein immediately after my workouts.
If you folks have any more questions about these (or any) topics, drop them down below. Thanks for reading!