If you realy want to loose weight,the first thing to do is to quit online gaming !
Your char may break a sweat fighting the bad guys or piloting in hostile space but your butt is glued for hours on the seat going nowhere. Shut down your pc.Take your dog for a long walk,ride your bike that started rusting in the cellar,join a gym or ask ur girlfriend to join you joggin in the park...
Life is OUT there !