Start here:

http://www.bodyrecomposition.com/nutrition/a-primer-on-nutri...

http://www.bodyrecomposition.com/nutrition/a-primer-on-nutri...

Then explore the rest of the site: http://www.bodyrecomposition.com/nutrition

When you're ready, start reading LeanGains:

http://www.leangains.com/2010/10/top-ten-fasting-myths-debun...

http://www.leangains.com/2010/04/leangains-guide.html