The best way ?
go to "a hot and sandy place" for 4-5 months - eat army food, drink 10L of water a day, walk approx 15k a day, oh and spend part of that time in a charcoal lined suit with all extremeties covered in rubber...
worked for me - I lost over 3 stone in 4 and a bit months
(problem was when I got home to a desk job and a wife who is a good cook, I put it back on in 8 months....
)