All meals and snacks are included, in fact you can get food 24/7. Paste the following into your address bar and you will find all the various options for dining, plus opening times http://www.princess.com/learn/onboard/dining/dining_options/sea.html.
Firstly, it's not possible to be anything other than Full Board on a cruise ship. Food on most major lines is available 24/7 & you can eat as many courses, as many helpings as you wish day & night. The only food you pay for is the 'Speciality Restaurants' which have a cover charge, should you choose to use them. Don't think 3 daily meals, think constant non stop food, free!
We went in August and at the beginning of the cruise people were eating 24/7 , by the middle of the second week you could hear people saying " we are missing dinner tonight , I can't eat another thing ".