What happens when you eat seafood at every meal for a year?

Peru anchovies

A pot filled with anchovies is seen aboard a fishing boat in the Pacific Ocean, off of Peru's northern port of Chimbote, in 2012. The anchovy pulled from Peru's waters is sold as fishmeal that feeds pigs in China and farmed salmon in Europe. It's also squeezed into increasingly popular omega-3 supplements.

Enrique Castro-Mendivil/Reuters

“What fish should I eat that’s good for me and good for the planet?”

Best-selling author and lifelong fisherman Paul Greenberg spent a year eating seafood for breakfast, lunch and dinner — and traveling the world — in an attempt to find out.

His quest is chronicled in "The Fish on My Plate," a 90-minute FRONTLINE special premiering Tuesday, April 25.

Meet Greenberg, and go inside the beginning of his year of eating fish at every meal, in this excerpt:

“Almost half the fish and shellfish consumed in the world is now farmed. Is that helpful or harmful?” asks Greenberg, the author of "Four Fish" and "American Catch," and a current Pew fellow in marine conservation. “I wanted to examine the fish on my own plate and take stock of what’s happening in the world’s oceans and fish farms in an attempt to find out.”

The documentary, produced by David Fanning, Neil Docherty and Sarah Spinks, follows Greenberg as he works on his upcoming book, "The Omega Principle," and consumes hundreds of fish meals in hopes of improving his health through a dramatic increase in his omega-3 levels.

With people worldwide consuming more seafood than ever, Greenberg also explores questions of sustainability and overfishing — traveling to Norway, where modern fish farming was invented; Peru, to witness the world’s largest wild fishery; Alaska, where 200 million salmon can be caught each year; and Connecticut, to visit a sustainable ocean farming pioneer who is trying to transform the industry.

Along the way, Greenberg comes away with surprising revelations about the seafood on all of our plates — including the fact that a piece of fish in an American restaurant travels an average of 5,000 miles before you get to take a bite.

And as far as the result of Greenberg’s yearlong, seafood-focused diet? Get the full story Tuesday night on FRONTLINE.

The Fish on My Plate premieres Tuesday, April 25 at 10 p.m. EST/9 p.m. CST on PBS (check local listings) and online.

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