Almost everyone on a cruise gains weight.  Typically, five pounds for a two-week sail.  There are exceptions.  If you get seasick, for one.  There are a few with a strong mind.  You can try to lose weight on tours.  Sleep, I learned, helps reduce gain. I've tended to increase from 5-8 pounds on a cruise.  I allow this to happen because it turns out that I can lose them all in a week or two when I get home.   Makes a case for this type of weight gain being mostly water .  We always get the full alcoholic drinks package, have at least two meals a day ( we tend to skip breakfast by enjoying a nightlife, whereby you wake up just before lunch ).  But two large meals, snacks and 10 drinks/day add up calories, especially when one doesn't exercise much, like me on a ship.  I'm still hesitant to use the wellness centers from those pandemic days. There was one exception.  We took a 52-day Seabourn cruise from Sydney to Honolulu....