Celebrity followers
Sarah-Michelle Gellar and probably many celebs in the 7 days before Oscar-night (but on the quiet!).

The theory
No-one claims to have invented this diet and attributions to originally being a hospital diet are vigorously denied. It is a rigid diet plan lasting only 7 days and no longer, and is aimed at kick-starting weight loss to the tune of around 10 lbs (5 kilos) in a week.

The plan

This easy-to-follow plan is designed to jump-start your diet and cause you to lose weight quickly.

Eat as much cabbage soup as you desire. The recipes vary slightly depending on which version you follow, but basically include a variety of low-calorie vegetables, such as cabbage, onions and tomatoes flavoured with bouillon, onion soup mix and tomato juice. Additionally each day of the seven-day programme has specific foods that must be eaten, including potatoes, fruit juice, vegetables, milk, bananas, and on one day, beef - which at least breaks the tedium of endless vats of cabbage soup.

Pros

• You'll lose weight quickly and can eat as much as you want of the prescribed foods.

Cons

• Many people who have tried this diet report feeling light-headed and weak, and notice a decrease in their ability to concentrate.
• It is basically a detox/fast which is not suitable for several circumstances such as for those with diabetes, diagnosed medical conditions, or those who have any eating disorders.
• The diet is too low in complex carbohydrates, protein, vitamins and minerals to stay on for an extended period of time.

One week.

Checklist

Restaurants: A non-starter unless you are prepared to take a flask of soup with you. It will be tough to find a place that serves that much cabbage.
Alcohol: No.
Caffeine: You’re encouraged to drink coffee or tea along with the soup.
Need to buy special foods: Yes - more cabbage than you can imagine.
Family friendly: No.
OK for vegetarians: Cabbage soup is vegetarian, but on some days you are encouraged to eat 10 to 20 ounces of beef.

The pros say:
Basically a very low-fat and low calorie diet will inevitably lead to weight loss. But it may also lead to digestive upset and light headedness. Fasts are usually only recommended when people can take time off work. While it is deficient in nutrients it won't do any harm as long as it is only followed for one week. It's not the diet for with someone prone to yo-yo dieting.