Dukan (ketogenic) diet
The Dukan Diet is a 4 phase diet, the first two phases of which are ‘ketogenic’. By total carboydrated restriction the body is essentially ‘starved’ and will enduce fat-burn. When the weight has come off you can reintroduce certain foods.
As with the Paleo and other low-carb or ‘ketogenic’ diets there is increasingly good evidence for their STRATEGIC (and supervised) use in weight loss and diabetes. However, left in the unguided hands of the dieter people tend to cherry pick which phases they do and often gut stuck on phase 1 which is OK for a kick-start but not nutritionally balanced for long-term use.
Other disadvantages of ‘ketogenic’ diets are low energy to begin with (while your body switches from carbs to ketones as fuel), chronic halitosis and managing the diet restrictions in a sensible way around your lifestyle.
See the general diet post for more sustainable approaches to weight-loss.