Recording Diet

I thought this is very interesting.
A Japanese man lost a lot of weight for six months or so by recording everything he ate.
There was a calorie chart book so that he could put calorie next to the food he ate. He carried a small notebook and kept recording everything. At the end of the day, he totaled all calorie. There was no restriction on what he ate, just wrote down everything. Once he got used to it, he started thinking how much calorie the food had before eating, choosing less calorie food. I think this is mind control.
Anyway, he was at a TV show, showing "before" and "after."