The following is not aimed at Matt, I just use his last post as an opportunity.

Weight, height, a body like knitting pins with a swollen head.. It is all the same argument.
Accept that the world is not tailored for you and learn to live with it. It is most often not your body that makes you go slower than optimum on the regatta course. It is what is inside your head. Most other reasons for poor performance are excuses made up by your ego to avoid admitting that other sailors know more about the game and trained harder than you did.

If somebody desperately feel that they need to gain weight or loose weight, there are eating strategies to fix that. Few are willing to study enough and accept the habitutal changes neccesary to have success with it.