It's no myth that our body weight will hover near a "set point" unless we make significant changes in our calorie intake and expenditure. Recently, I've decided that I'd be happier with a somewhat lower body weight. (Okay, I'd be even happier with a significantly lower one, but realistically, that's not going to happen.) Perhaps coincidentally, my husband currently is trying to increase his by a few pounds. But most of us will never have the task of trying to gain weight, so I'll focus on how to drop, not add, to our set points.
I've looked into what it would take to coax my body into settling about five pounds lower. Once you achieve a certain set point, you have to work pretty hard -- or splurge big-time for a sustained period -- to move it again.
I found a really helpful site that explains the body weight set point concept and gives instructions about what to do if you want to change it. Click here to read the details.
Just a few piece of info that I especially like from this site--
The core principles of changing your set point are to Eat less/shed pounds; Eat well (healthfully); Move more; Sleep more; Stress less.
Weigh yourself daily, and write down what you eat. (But before you try to change anything, start by writing down what you have been eating.)
At the end of each day, code your progress by the R-K-O Method as follows: If you have eaten healthfully and exercised sufficiently, give yourself an R (for regular reducing). If you do one or the other but not both -- eat well or exercise -- you get a K (for keeping the same). On any day that you basically blow it all off, eating too much and slugging out, score it an O (for off day). Try to have as many R's as possible, especially R days in a row, and you will lose weight and start moving your set point.
I have bookmarked this -- http://www.bidmc.org/YourHealth/BIDMCInteractive/BreakThroughYourSetPoint (see full link highlighted above -- because it seems highly useful. Included are videos, podcasts, charts, a food diary template, and lots of other crutches that you might want to consider using.
The site also advises not to try to lose more than 10% of your weight, and notes that losing even a few pounds (and keeping it there, thus lowering the set point) has significant health benefits.
(In this cartoon below, I probably resemble the middle figure more than the others, and really am not going to look a whole lot more like the girl to the right of that. Still, I'd like to take a few steps in that direction.)