[tpeng]

I've met a lot of people who say that calorie counting doesn't work, but I haven't met a single person who consistently and meticulously counted calories over a long period of time, eating at a caloric deficit, who failed to lose weight.

[cschmidt]

The argument is that you won't keep off the weight. See chapter 2 of Why We Get Fat by Gary Taubes. If you turn off the calorie restriction, you gain all the weight back, and more.