While swimming is great for increasing lung capacity, toning muscles, and even helping to burn off excess tension, Harr says the surprising truth is that unless you are swimming for hours a day, it may not help you lose much weight.”Because the buoyancy of the water is supporting your body, you’re not working as hard as it would if, say, you were moving on your own steam — like you do when you run,” says Harr.
Further, he says, it’s not uncommon to feel ravenous when you come out of the water.
“It may actually cause you to eat more than you normally would, so it can make it harder to stay with an eating plan,” he says.
url: http://www.webmd.com/fitness-exercise/features/top-9-fitness-myths-busted?page=2