Just thought I would add the names of 3 restaurants I can recommend.
1. V.I.P restaurant and bar- between Caldas da Rainha and Foz do Arelho. Good reasonably priced local food, charming Canadian waitress- gizzard soup and sea bream excellent.
2. Cais da Praia- on the beach at Foz, excellent seafood- squid, octopus and cuttlefish.
3.A Lareira - really fine-dining in the middle of a pine forest between Rainha and Foz, smart upmarket, good service, large portions of very good food. Seafood stew and steaks delicious.