On September 21, 2015, lifelong fisherman and best-selling author Paul Greenberg had his blood drawn, and then he started being a strict pescatarian. For a year following that date, Greenberg ate seafood every single day, sometimes for breakfast, lunch, and dinner. The experiment was part of research for his forthcoming book, The Omega Principle, which will investigate how the health of the oceans ties into our own health.

Especially in light of the livestock industry, which is responsible for around 15% of global greenhouse emissions and, particularly when it comes to beef, a host of health concerns like high blood pressure and heart disease, a shift toward more fish consumption seems like a positive step in advancing sustainability in our food systems.

After a year of eating fish, Greenberg’s levels of omega-3 were indeed extremely high, but when his test results came back, his blood pressure was slightly elevated, and the accompanying high levels of mercury in his blood, his doctor told him, likely wiped out any of the gains in mental fortitude meant to accompany increased intake of omega-3.

But he has a plan: After learning, through the process of making the film and writing The Omega Principle, how to select sustainably farmed and harvested fish, he’ll stick to choices like farmed mussels, clams, and oysters, “which make the sea better as they feed us,” Greenberg says. “I’ll keep eating fish, but not every fish, and not every day.”

Read the source article at fastcompany.com