This is an excerpt from the new Atkins book, out in America but not yet in the UK:
Chapter 6, page 67
"Don't count calories, although we do ask you to use common sense. In the past, some individuals made the mistake of thinking that they could stuff themselves with protein and fat and still lose weight. If the pounds are falling off, forget about calories. But if the scale won't budge or it seems to be taking forever to lose, you might want to do a reality check, caloriewise. (See page 107.) You could probably guess that too many calories will slow weight loss, but here's a surprise: too FEW will slow down your metabolism, also threatening your progress."