The art of losing weight basically comes down to a simple equation:
The amount of ingested calories has to be lower than the amount of calories consumed (worked off) by your body.
It does not really matter if you stick to Atkins, SouthBeach or any other special diet scheme.
It is true though that - at least in biochemical theory - dietary fats will only be turned into body fat if you also eat some carbs, because the reactions involved in the build-up of body fat do require tiny amounts of carbs. Reality is that it is virtually impossible to eat a absolutely carb-free diet, since almost no food is totally carb-free. So don't try out a high-fat zero-carb diet at home...