Not sure how feasible this is, however I thought it might be an interesting project to try and modify a pair of shoes to be able to log weight over time.
Initially I thought of just being able to weigh a person over the duration of a day as opposed to the more common weigh-in between days. So I was thinking along the lines of a pair of load sensors as insoles along with accelerometers/gyros on the thighs. When the thighs are near horizontal then you are likely to be sitting down so the load sensors would not get a true weight reading and thus can be marked as such or ignored. Also when the accelerometer is showing a large displacement (e.g. when walking) then once again a true weight reading is not likely to be possible. However at some point in the walking process there may be a point where a true reading at the sensors in the insoles can be made and logged. If not, then logging only when standing would be another option.
However, I then thought of other uses for this type of sensing such as monitoring additional weights involved manual handling activities and perhaps with more sensors sewn into a pair of overalls then one could start to detect posture and alert the wearer if they are stooping whilst attempting to lift heavy loads potentially resulting in cumulative back injuries.
And for the gamer of course then perhaps a wearable Nintendo Wii Balance Board type game controller. Although anything involving stepping on and off the balance board would require additional emulation in the controller.