If you set your race sag to 4", your free sag should be between .39" to .98". Once the race sag is set, if the free sag is less than .39", then the shock is too soft for you. The stock XR650R's stock shock is designed for the average ungeared rider of 165 lbs. At 230, you definitely need stiffer shock and springs. Check out
www.racetech.com, the shock cost around $89. I forgot how much springs cost, but your shock is the more important of the two. For more info on setting up your race sag, check out
http://www.bajadesigns.com/suspen.html
Concerning the diet, try switching to Jack In the Crack, much healthier :)