I never do it intentionally--but when I look back and notice that I've been consistently on, or under, my calorie range every day that week--I plateau. If I have one day (I call it a "hiccup day") where I went crazy and ate anywhere from 1800-2500 calories, I lose the most. (and that one day is typically a tuesday-friday--Weigh In is Monday)
When I was doing WW, I tried the "Wendie Plan"-- but it seemed that the intentional shifting didn't do much more for me than hitting my points range every day did.
However--when I was dieting the first time (in my Teens) I lost the weight REALLY quickly just hitting my points target every day... So my body has changed a lot in 5 years!
I've learned that the best way to find out what works is to just try it for 2 weeks... and I know that's super scary (especially if you're just starting or SO close to goal you can almost touch it!)--but doing that has taught me SO much about how my body works.
Good luck!
