In one word...change...but if it's not a good change, the changes resulting won't be either.

I used to keep my weight with low fat and a LOT of exercise, and when I moved and couldn't do that much exercise anymore, the eating low fat didn't seem to do a BIT of good!

Now that I've done it AGAIN with low carbing, I know I have to be vigilant, but I think it's easier to stick with low carbing than it was to figure out a way of exercising an hour & a half a day...which I enjoyed, but got too busy/poor/etc to do anymore.

I think vigilance is the key. Throw out the bigger clothes, so you HAVE to face the fact that certain things are getting snugger, and it's easier to stop the slide at the top, instead of the bottom.