TIY set point begins at conception.   R: Each day that you follow a healthful diet and get enough physical activity is an "R" day of "regular reducing." K: What if you manage to keep your eating in check but don't get any exercise? That counts as a "K" day for "keeping it off." The same goes for when you exercise enough but eat more than you planned. Your weight will likely stay the same. O: Days when you splurge (particularly during holiday season) are "O" days for "off." The number on the scale will go up, because you ate too much and/or didn't get enough physical activity.   http://i.imgur.com/IY0Q5it.jpg