The easiest way to lose weight is simple - just make sure your calorie intake is lower than the calories you're burning. Doing this is easier said than done though, especially with swimming. Recent research has shown that whilst swimmers typically burn just as many calories as runners or cyclists, it's what they do AFTER swimming that negates all the fat burning effects of their workout.
It turns out that swimming in cold water - anything below 30 degrees celsius, triggers a survival mechanism in your brain which basically tells you to "EAT EAT EAT" - to put on weight to counteract the temperature difference your body has detected in the environment (and so ensure your survival). This is why, after a long swim training session you can feel very hungry.
So you've swum a couple of k's in cold water and you get out feeling starving hungry and what do you do? You go and stuff yourself silly with a large meal to satiate your appetite.
So what do you do about this problem?
Well, you could of course just not eat anything and fight the hunger pangs. Personally I take a stick of chewing gum (low calorie of course!) to the pool. Chewing the gum fools my brain into thinking it's got food and stops me feeling hungry pretty quickly. I can then eat a sensible meal later on and reap the rewards I deserve for all my hard work!
It's amazing how obvious it is when you think about it. Since pointing it out to people in our private swimming lessons they've seen a dramatic improvement in weight loss with no extra effort involved. Brilliant!