You can display a button for each milestone as you reach it or use a couple of buttons to add up to your current weight-loss level if there isn't a button reflecting where you are currently (like I might use a 5lb. and a 75lb. to show that I'm at an 80lb. loss). You could even add each button to your blog with the date you reached that milestone. Feel free to be creative!
To grab your button, just copy the code under the appropriate button and add it to your blog's sidebar.
Feel free to visit Honey's blog and tell her thank you. I only had the idea, she's the graphic design talent behind the buttons. While you're there, be sure to check out her weight-loss story.
Buttons courtesy of: