“Diners, Drive-ins & Dives”

(8 p.m., 11 p.m., Food): In the new episode “Triple D Nation: From the Sea,” host Guy Fieri is all about the seafood, starting with a New Orleans oyster shack that is putting a new spin on that longtime local favorite. If the Italian food at an eatery in Geyserville, Calif., tastes authentic, there’s a good reason: The cooks at this family-run business rely on their grandmother’s cookbook for their recipes. Finally, Guy revels in food that tastes truly south-of-the-border at a Mexican restaurant in Phoenix.