I gained 5 pounds on a 7 day cruise. I was eating like 6 meals a day.

8am - breakfast w/ family (bacon, eggs, other good stuff)
11am - brunch (burger, pizza, or sandwiches at one of the little shops)
1pm - lunch w/ family (something fancy in the ship's dining room)
4pm - afternoon snack (ice cream or pizza or something)
8pm - formal dinner (I normally got the steak/beef option)
10pm - booze at the club
1am - pizza or sandwich before I hit the sack

It was absolutely disgusting how much I ate that week. It's so hard not to indulge when you are surrounded by fantastic free food everywhere you turn.