I have been CrossFit training for about 6 months now and I love it.  I was getting very strong and I had increased endurance but I wasn't losing any body fat (which is what I was hoping for).  Here is a sample of weight and body fat measurements from August (all measurements were taken with a Tanita BF-683w scale):



I was playing around with the paleo diet at that point but never really committed to it.  Finally, on September 10 I decided to go strict paleo and check out what happened.



I dropped 4.8 pounds and almost 2% body fat when I added paleo to my workout routine!  Now I know that measuring body fat with these scales is not the most accurate method, but I certainly believe any strong trends that show up.  And this is definitely a convincing trend.  My weight has since settled into the 138-142 range but my body fat has continued to go down (measured 12.4% this morning).  Just goes to show you how important it is to include proper diet with your training.