Simplifying the problem to the barest elements, he models the human body as a "rubber bag," where variables such as food type, frequency, metabolic rates and even exercise are considered negligible.
While the diet is a fairly straightforward calorie-counting approach, data smoothing (exponential moving averages in particular) is considered a key element of the monitoring system.
Walker presents techniques for Excel-aided or paper-and-pencil data smoothing to allow the dieter to adjust the diet for themselves using the long-term trend and to not be discouraged by short-term fluctuations based on water retention or other factors.
A quick check of the trend line provides an easy way to make small adjustments in intake, allowing much greater control of weight for life.
[5] Walker also provides a free online tracker and grapher at his Fourmilab website, and the program Eat Watch, mobile tracking and charting services for the Palm platform.