Let's be honest here: If you're looking to lose some weight, you've got to take a hard look at your diet and jump on the treadmill a little bit. That being said, signing up for a triathlon will provide you with so many other benefits (like the previous nine, for example), that weight loss is just the icing on the cake. So if you're seeking a heart-healthy, fun, social, motivating, mind-boosting and libido-humming activity that also makes your favorite pair of jeans fit like a glove once again--sign up for that triathlon (and maybe plan a little post-race shopping spree).