The amount of gravitational pull you feel is partly offset by centrifugal force, which varies depending on how close you are to the equator, and on how far you are above sea level. According to your bathroom scales, you weigh more in Edinburgh than in London.
Hmm, I was fatter when we lived up in Newcastle. This checks out.
Alternative weight loss techniques include making the planet spin faster or else hollowing it out entirely, neither of which would have any negative repurcussions as far as I can see.