Amazingly enough, in the Journals section. not to worry, the sections in this forum aren’t all that easy.

http://forum.lowcarber.org/forumdisplay.php?f=36
Read the top two "Stickies" or pinned posts about how to write them, then a Journal button will show up on your posts. Journals can be a list of what you ate or your thoughts on the meaning of life. More the journey though, because....

Then there is also a Success and Milestone section. http://forum.lowcarber.org/forumdisplay.php?f=86
I’ve not quite figured out the difference, and why one is a folder behind the other?, but again a button will show up on your posts if you have done one.
Ken and Grav are experts how to write in both a journal then record a success story too.