What's Willpower Got to Do With It?

Depends on who you ask.  Who of us has not been disgusted over a lapse in our diet or exercise plan?  There are those who believe that such lapses evidence a serious character flaw -- you know, the just push yourself away from the table, that's the only exercise you need, suck it up and make it happen kind of people.  This is a complicated subject for me.  At times I have been disgusted at the lack of, and at other times, particularly recently, amazed at the self-control I can exercise.  Tara Parker-Pope blogs on wellness in the New York Times (http://well.blogs.nytimes.com/2011).  On February 28, 2011, she wrote about an emerging body of research on the topic of self-compassion.  Preliminary research suggested that the "cycle of self-criticism and negativity" generated by those who beat themselves up over not measuring up to their own expectations for change causes failure, not success.  The hypothesis is that feeling bad only leads to more bad behavior.  Self compassion involves caring about oneself, being kind to oneself just as we would be kind to a friend or family member in the same situation.  A Harvard-based psychotherapist, Jean Fain, said that, "self-compassion is the missing ingredient in every diet and weight-loss plan."  Not sure I agree with that conclusion, since the structured programs like Weight Watchers emphasize progress and not perfection.
What makes more sense to me is her blog entry on December 6, 2007.  At Canyon Ranch, "willpower" was noted to be unreliable as a behavioral strategy.  Parker-Pope concludes the same.  "What researchers are finding is that willpower is essentially a mental muscle, and certain physical and mental forces can weaken or strengthen our self-control.  Studies now show that self-control is a limited resource that may be strengthened by the foods we eat.  Laughter and conjuring up powerful memories may also help boost a person's self-control.  And, some research suggests, we can improve our self-control through practice, testing ourselves on small tasks in order to strengthen our willpower for bigger challenges...BUT THE RESEARCHERS ALSO FOUND THAT RESTORING GLUCOSE LEVELS APPEARS TO REPLENISH SELF-CONTROL."
What this means to me is that the maintenance of glucose control (evening out the highs and lows) is conducive to self-control and that's why it's becoming easier to control cravings.  Anyone else out there agree?