I think both Jenn and Agonycat have it right. Of course us newbies are fretting for all the reasons Jenn says. And yes, It probably does bring us up short and make us realise its a bit daft, once we're ready to learn that - it has to be a bit of personal experience too and maybe we have to go through the micromanaging bit first before we realise we're driving ourselves nuts!
For me, part of the issue was becoming conscious of my food and weight after quite a while of almost deliberately ignoring both. So once it was in my mind, I started to think about it all the time.

Bit like the housework - I walk past dust and chaos everyday when I'm doing other things and i really don't notice. Then I have a clearing up day and start to see the mess - if I don't get finished clearing up then, the mess that I used to walk past bugs me rotten because I've become conscious of it!

Most of us will graduate to sensible, WOL people and the discussions and advice in this forum will help.