"Knowing that I'm accountable for my decisions makes me much more likely to make positive choices."

I found a very similar effect when I started taking pictures of everything I ate and drank for a few weeks. My intention was to eventually write an iPhone app specifically for taking these pictures and tagging them with food items, having the phone tabulate overal nutrition information ,etc.

Turns out I never ended up having time to write that app, but what I noticed was that the simple act of taking the pictures (without ever reviewing them) was enough to force me to stop and think about what I was about to eat, and that was enough to affect a change in my diet.