No... I'm not jealous.
Well you could start with eating sensibly... drop all that fast food (Chinese fast food ain't so bad for you, it's hand made for a start.) and get loads of walking done, soon you'll be fit as a fiddle. I used to go rambling every weekend from Central to Stanley, take a few hours like. Grab a camera, and tons of film, on a good day you can see for miles. Oh, don't forget water! You'll need that most of all - there's not a shop around for miles, miles and miles.
My first attempt nearly killed me, being a smoker and all.. but i've since given up. Me a proud non-smoker now I managed to lose almost 5-6 Kg's just by walking around HK looking for clients. My typical day started at 8am in the morning.. and at 3am, the next morning, I'm still in Dragon Eye. Greatest part is, my Cantonese went from non-existent to almost fluent in a year!
I miss Hong Kong....
*crys*