You can find a Ticker that make that automatically here:
http://www.ketoforum.de/diet-ticker/weight-loss.html
- register
- login and "create Ticker"
- put the code in your signature
if you want to update your weights just go to the Ticker again and
- login and "change weights"
Now your Ticker is updated everywhere yout placed the code.
BTW: You can use "lb" or "kg" :-)
best regards
Ken Clark