I eat it about once a week. Depends where you live--it's easier on the coasts to get fresh seafood. It can also be expensive.

I don't think eating just any seafood is healthy--I think the twice a week number comes from the benefit of Omega-3 and Omega-6 fish oils, but you can also get the benefit from taking fish oil capsules. But it's oily fish that are best, and small oily fish like sardines and herring are the least harmful for the environment and depletion of the oceans while also lowest in mercury. Large predator fish are high in mercury which isn't healthy, therefore consumption of swordfish, marlin, and some tuna should be avoided or minimized.

So I think the seafood choice is complicated. Shellfish like shrimp, crab, and lobster don't do much for health, some fish are too high in mercury, many wild fish are overfished and populations are being depleted, and most farmed fish pollute the oceans or other water sources and are fed feed made from other depleted fish species.

The best fish to eat would probably be sardines because they are low in mercury, are not being depleted from the oceans as fast, and they have lots of healthy fish oils. But they don't appeal to many people because the healthy fish oils give them a strong fishy flavor and odor, and because they aren't huge filets of fish steak that people crave.

I could eat seafood every night. We eat it about 3 times a week.