May be a bit ambitious, depending on your previous activity/exercise level. The last thing you want to do is be all gung ho, get burnt out and quit after a few weeks. The actual plan looks ok if you're up to it, but I'm guessing that if you need to lose 20lbs you may not be. If you can do it, great, but don't hesitate to back off some and add some rest days if it seems necessary. Lasting change comes form lifestyle changes, not brief flurries of intense training programs.