Although rumor has it that most people gain five pounds or more on a cruise, you only do that if you let yourself -- heaping up your buffet tray, sitting in the Jacuzzi drinking beer all day and ordering every course at dinner. Admittedly, the cruise lines make it very easy to overindulge, but to paraphrase Goethe, "Self-restraint is the first mark of the master." Enter, please, the door marked "debate," and see where the breadcrumbs lead . . .

Matt: So the question of the day is, "Is it possible to avoid gaining weight on a cruise?" And the answer is yes. It is possible. Just don't friggin' eat so much.

Heidi: Yeah, really, just put that dang fork down and close your mouth. Of course for some people that's easier said than done. Me, I make a point of always taking the stairs on a ship -- I figure that'll burn off at least two or three slices of pizza every day.

Matt: Personally, I think it has something to do with our capitalist economy. People get so focused on the money value of everything that when something's free -- or at least seems like it's free, since of course they did pay for the cruise -- their lizard brain kicks in: Must eat everything now.

Heidi: I think the concept of overeating "because it's there" pre-dates Adam Smith. I mean, what was a Roman Bacchanal after all? The ancestor to the midnight buffet.

Matt: You may be right. Heck, they used to line up for toilet paper in the Soviet Union, and that stuff doesn't even taste good.

Heidi: Taste, unfortunately, doesn't always have much to do with eating. I keep trying cruise ship desserts, for instance, even though so many seem to be made from the same bland pseudo-mousse that's just molded into different shapes and given different names. On the other hand, my husband Arun and I couldn't keep ourselves away from the Indian vegetarian food in the Norwegian Dawn's buffet restaurant. It didn't matter that we had dinner reservations somewhere else an hour later.

Matt: I'm with you on that one. Yum. I tracked down the Indian food on Norwegian Jewel when I was on it. The spread is hidden way back in the corner of the indoor/outdoor buffet. Maybe that's a tactic for keeping the weight down on your cruise: Don't eat anything unless it's really hard to find.

Heidi: That, or run 100 laps around the ship's jogging track before every meal.

Matt: Aboard most megaships these days thatÂ?d be, let's see . . . forty miles.

Heidi: If Forrest Gump could do it . . .

Matt: Ew, that awful movie. Remember, life's like a box of chocolates: loaded with sugar and empty calories that'll make you fat, miserable and diabetic.

Heidi: Oh well now, since when do you only eat carrot sticks and wheat germ, Mr. Null? IÂ?ve seen you eat those 7-Eleven nachos with the fluorescent yellow cheese goop.

Matt: You obviously don't know about yellow cheese goop's incredible curative powers. You can clean paintbrushes with it too.

Heidi: Well, I don't know about that, though I did hear that Baked Alaska makes really good caulking for bathroom tiles.

Matt: Maybe that's the secret to keeping the pounds off: work. Swab the deck, paint the hull, caulk the bathrooms -- just like in the Coast Guard. I think I lost weight helping haul the anchor on a Maine Windjammer Association schooner last year. Then again, I also lost weight on a Princess cruise in Mexico just by never taking a shore excursion. I walked around all the ports instead. Covered about ten miles a day.

Heidi: Yeah, I did some heavy lifting on a couple of Windjammer Barefoot cruises in the Caribbean -- and I don't just mean chugging the Red Stripes. I was pulling the lines, crawling around the bowsprit, and diving off the side of the ship. Nothing like a good hearty swim to burn off breakfast.

Matt: "A good hearty swim"? That sounds so Victorian. Did you take a constitutional after, and sip bouillon? But back to the point: Cruise ships encourage overeating. Look at the plates in the buffet restaurants. They're the size of serving trays.

Heidi: And how many passengers order two and three helpings of each course at dinner? "I'll take two lobsters and a cordon bleu please." No wonder Americans are the fattest people in the world -- it's the cruise lines' fault!

Matt: Yet Germans love to cruise too, and look at them: Every German you see on a ship looks like a former Olympic athlete. Ditto for the Japanese, who never seem to gain an ounce. What's to explain that?

Heidi: Simple. Germans ride their bicycles everywhere and everything the Japanese eat is really small. Americans, on the other hand, tend to get lazy and are obsessed with BIG.

Matt: So there you have it. Now watch, though: The next big ship that launches is gonna have a sushi bar full of exercise bikes. The mo

re you pedal, the more sushi you get. And will we see a dime for coming up with the idea? We will not.

Heidi: True, true. Has our brilliance ever been justly rewarded?

[Awkward pause.]

Heidi: Ahhh, eeehhh, soooo . . . what were we saying? 

Matt: Something about sushi, which you actually can get on a lot of ships -- Crystal, Princess, Celebrity, NCL, and Carnival, last I checked. Did you know kids apparently love sushi? I read that somewhere.

Heidi: Maybe that's the solution to obesity among America's youth.

Matt: Maybe. But wait, is sushi really low-cal, or is it just small and expensive?

Heidi: The real problem is it wouldn't do well in vending machines.

Matt: Good point. To be fair, though, most of the cruise lines have some variation on "spa cuisine" too, so if you have the willpower you can actually eat healthier at sea than at most restaurants.

Heidi: That's very true. My husband never gains an ounce when we cruise.

Matt: Does he eat the spa cuisine?

Heidi: Sometimes. But mostly his trick is no snacking and an hour at the gym every day.

Matt: And he's also got good genes. Hey, maybe that's the way to stay skinny on a cruise: have skinny parents.

Heidi: Yeah, that or wire your mouth shut.

Matt: That'd work.

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