Some people starting the 6-week challenge have not read or finished Dr. Fuhrman's healthy eating books. I highly recommend reading either Eat to Live or Eat for Health. I think until you ingest the information, you will not understand fully what healthy eating really is and what it can do for you. In the meantime, here is a set of posts I've written in the past on healthy eating that might help guide you a bit as you get started:
http://veganbarbie.blogspot.com/search/label/healthy%20eating
Here's another link Jim sent me today that could be very helpful for someone starting out:
http://www.21daykickstart.org/
It's a program to try healthy vegan eating for 21 days.
Also you may be motivated now but if you need a little help later, here are some posts about motivation:
http://veganbarbie.blogspot.com/search/label/motivation
