I have been on Kuvan for about 1.5 yrs now.. and it has made things alot easier.. the only side effect i see is partly my own fault... I was able to increase my protien intake from 12 gms a day to 30 gms a day.. Yes i kow that is awesome!... but over time.. especially the past 2 months.. i have in a way lost track of how much i eat... I have made very in depth charts to keep track of things.. and it broke everything down to a science.. how much i ate.. the average i ate a week.. how i felt in 6 diff. catagories.. and the averages.. and a line graph to show where was to correspond with how i felt.. So i didnt want to keep counting DAYS... i dont want to do that.. so i stopped... now i am at a point with my Kuvan.. where i push the limit.. every day.. for the past several months... instead of 30 gms i had about 38 upper 30 most of the time becuase i estimated instead of keeping an actual account of how much i ate.. in the past few weeks that has jumped to 40ish gms a day... thats too much... i have not felt that well in a few months.. i woke up today.. more tired then when i went to bed last night.. i wanted to go right back to sleep.. with 5 kids and me being Mr. Mom that was impossible... Dr appts for the kids all day.. headaches the past several days... and thats what takes me out.. so yesterday i started keeping a more accurate accound... 24 gms yesterday... and about 33 today.. its so hard! really really hard! off the diet for 25 yrs i know eveything.. from Pizza to eggs.. mmmmmmmmmmm so we will see the average... this week... 24 and 35 so far this week..