In the first stage of the Dukan diet, dieters are advised to eat lean proteins such as chicken, turkey, fish, lean beef or eggs. In addition to unlimited quantities of lean protein, dieters consume at least 1.5 tablespoons of oat bran and 1.5 liters of water per day.
The first stage lasts from one to 10 days, based on how much weight the dieter wishes to lose. In the second stage, dieters are permitted to add unlimited amounts of non-starchy vegetables to the lean proteins, on alternating days. So, for instance, one day the dieter consumes only lean protein, oat bran and water. The next day, the dieter may also consume any approved vegetables. There are 28 approved vegetables; examples include: tomatoes, carrots, bell peppers, broccoli and cabbage. The second stage continues in this alternating fashion until the dieter reaches their weight-loss goal.
In the third stage, dieters may eat lean proteins and vegetables every day, and may add one piece of fruit, two slices of whole-grain bread, and one serving of hard cheese each day. Dieters may also have one or two starchy foods and one or two meals each week that are unrestricted. This is a transitional phase, intended to let dieters adjust to eating diverse foods without gaining weight back; it lasts five days for each pound lost.
The final maintenance stage is intended to be ongoing. Dieters eat whatever they want for six days of each week, and follow the protein-only rules from the first stage for one day each week.