Men always have the mentality to forget about all their problems on a cruise, thinking that they don't need to worry about anything. They just intend to relax, enjoying their vacation. They don't care about anything and just want to go with the flow, hoping to deal with everything else when they home. They never realize how much those thoughts impact their bodies.
Exposed to the endless buffets and continuously available menus across the ship, they lose all inhibitions. The moment they feel any hunger pangs, they need to eat, taking little time to end up at one of the plentiful restaurants on board. They don't think twice about ordering as much food as they can, wanting to take advantage of the trip they paid for, ordering appetizers and dessert every chance they get.
Halfway through their cruise they're already growing out of their clothes, their swim trunks visibly tighter and tighter on the pool deck. Their constantly full bellies push out in front of them, sinking below the belt line from how much weight they've gained, stuffed their stomachs with food.
Even when they notice, they don't give it two thoughts, letting their apathetic ideal take over. They let it slide until they get home, but while on the boat see how much they can eat. They want to see just how big they can get before it all ends, not realizing they'll be popping out of all their clothes once they return.