The problem with relying on hunger is that, for many people, that hungry signal doesn't shut off at the right time. The Hacker's Diet[1] goes into this in great

The problem with relying on hunger is that, for many people, that hungry signal doesn't shut off at the right time. The Hacker's Diet[1] goes into this in great detail, but the gist is that scale weight + calorie counting is a good proxy for replacing a broken hunger signal. This is one of those things that's really hard to understand unless you experience it, so don't worry if you don't get it. [1]: http://www.fourmilab.ch/hackdiet/ http://www.fourmilab.ch/hackdiet/