It is possible to lose some weight on the seven-day cabbage soup diet, states Mayo Clinic, because it restricts calories and nutrients. There are no statistics available for average weight loss on the diet.
Proponents claim dieters can lose up to 10 pounds a week on the diet, states WebMD. Participants eat cabbage soup every day, with new foods gradually added as the week progresses. Many use the diet as a way to kick-start weight loss, although the Mayo Clinic advises dieters not stay on the diet for more than a week at a time because of the lack of nutrients. The diet is a short-term solution and may be unhealthy or even dangerous, cautions WebMD.