In an effort to justify my Palm Tungsten T to myself, I also bought a diet tracking proqram. Really because I want to see what I eat every day and compare it to the ideal. So after only 2 days, I have a good idea of what foods to reduce and increase.
Seeing the numbers converted into graphs drives the point home. When even the Palm Pilot tells you're fat (I didn't know it could talk), it is time to hit the gym.