The news has pretty much exploded over the Internet recently. The two doctors are going to court over libel.
Personally I find the negativity towards the Dukan diet shocking. Most people who rush to diets aren't eating many vegetables in the first place, so the fact that they start cooking and trying the veggies from the allowed list (there are PLENTY of those available) should be a reason to celebrate, not complain.
Check out this article and video at ABCNews for some details on the lawsuit.