Last time I lost the weight it was by, as someone else mentioned, eating smaller meals more frequently. Personally I have to eat more calories a day than most (1800) because of some unique health issues, but I find that as long as I can walk 2-4 miles 3-5 days a week, and come as close to that 1800 as I can, I lose weight almost every day. Right now, that number is creeping upward because I don't have my pain pills, and lots of binging because I am so depressed about it!
I switched almost all of my foods at once, but I allowed (still do) one day a week where I could eat a couple of things that aren't so "healthy." I believe the flex-points work in a similar fashion?