Forget dieting, forget running in the rain and being attacked by dogs, forgot getting sideswiped by buses whilst riding.
Once in the Wii plaza, you can set up your own Mii which is sort of a copy of you for your journey.
Once you designed your Mii you can do the body test to see just how old you really are and your weight which is kept like a diary. Graphs tell you when your going up or down in BMI & weight. Enough of the boring stuff, onto the fun bits.
There are about 15 games to start with, as your play more, you unlock better games & harder difficulties.
There are balance games to see how well you can stand on one foot, aerobics for stepping, jogging, dropping marbles thru tables, and a whole heap more. My fav being the ski jump.. Anyway plenty of things to do here and all in the name of getting you FIT... Spend hours doing this and it may just work. Have fun...