You've turned many pages, and turned over many difficult concepts in your mind since we embarked on our quest for an eat watch. Finally, our quest has come to an end.
The original dream was of a device that monitored, moment by moment, the calories we ate and burned, that told us when to eat and when to stop. On our many side-trips into apparently unrelated areas of engineering, mathematics, and management, we've found a way, starting from nothing more than daily weight, to accurately calculate the balance of calories eaten against calories burned. We've discovered the simple link between this calorie balance and weight gain or loss. Finally, we've developed a way, meal planning, to accurately control the number of calories we eat without disrupting our meal schedule or forswearing the kinds of food we enjoy. Taken together, these techniques constitute an eat watch: they monitor calories in and calories burned (actually their balance, which is all that matters), and they tell us how much to eat, and when.
The long-sought tool of weight loss and permanent control is now ours. In the next chapter we'll turn to the practical steps to put it to work.