How to lose weight on a cruise

I was interested to read that cruising has been mentioned as the perfect way to lose weight.
I was shocked to read this because as far as I am concerned it is completely the opposite. I always diet and exercise before I go to try and lose as much as I can because I know once on board I will manage to put it all back on again plus more so back to the diet and gym as soon as I get back
I really wanted to know how others manage to stay slim or even lose weight while enjoying their cruise.
Here is what the author of cruise yourself slim suggested:

1/ Use the wrong hand to hold your cutlery so taking longer to eat your meal and knowing when you are full.
2/ Use chopsticks to slow down your food intake
3/ Put cutlery down between mouthfuls again to slow down you food intake
4/ Chew your food properly as studies have shown that people who chew their food more thoroughly lose more weight than those who don’t
5/ Drink more with your dinner ( don’t think this applies to wine, shame as this might have been more to my liking )
6/ Sit down to have your meal

Now most of these would fit into a cruise holiday but all I can say is how boring is this and surely we are allowed a few weeks of self indulgence where it doesn’t matter if we gain a few pounds as long as we are relaxed and enjoying ourselves.
There are other ways to keep on top of your weight on a cruise. Most ships have a fully equipped gym with a variety of different classes available. There are running tracks, rock climbing, Rollerskating, Surfing etc etc depending of course on the ship that you choose and you won’t feel like this is a chore as it is all part of your enjoyment.
My advice would be to go on holiday and enjoy yourself and if you gain a bit of weight you can always lose it when you get back.