I've dropped 20 pounds...from 225 to 205 at 6'1". I've never been a runner, although I did my first sprint tri early this year, and do as many 5ks when it's not so frigging hot here in Texas. My best 5k time is 40 minutes flat. I wonder how much faster I'll be with the 20 fewer pounds.
Who knows? maybe aerodynamics alone will shave another 5 minutes off