HealthLine.com reports that the seven-day cabbage soup diet is potentially dangerous because it is nutritionally unbalanced, extremely high in sodium, and void of calcium, fat, protein and B vitamins. There is also a probability of flatulence and gastrointestinal problems due to high cabbage intake.
The cabbage soup diet is designed for short-term weight loss, as cabbage is low in fat and calories. However, this diet causes the body to lose water weight and muscle mass instead of fat, which slows the body metabolism and actually leads to fat storage and weight gain after resuming a regular diet. Dieters on the seven-day cabbage soup diet may experience low energy levels and weakness. Moreover, there is no exercise regime or lifestyle change associated with the diet plan, and the body is subjected to nutritional deficiencies if done for an extended period of time. Dieters should consult with a doctor before starting this diet.