I wouldn’t go on a crash diet as it not the healthiest or safest way to lose weight. But here’s the information anyway.

If you have just a little weight to lose, and want to take it off fast (say, so you can fit into those great pants for your cousin’s wedding), there are a number of diets that you can use. Most of these wouldn’t be recommended for long-term weight loss, as they substantially restrict your intake of some essential nutrients, so using them habitually may not be healthy. But if you’re normal diet is healthy, and you just want a quick boost to drop 8-10 pounds quickly, or to kick off a new diet with a bang, the Cabbage Soup Diet actually works.
The cabbage soup diet has been around for nearly 30 years. It’s based on the notion that your body actually uses more calories to digest cabbage than the amount that it derives from cabbage.

It’s a so-called ‘negative calorie diet’, and includes many foods that, like cabbage, are high in fiber and very low in calories.
The base of the cabbage soup diet is - what else? Cabbage soup. There are several recipes for cabbage soup available. Essentially, the soup is made with onions, peppers, mushrooms, carrots, cabbage, celery and spices to taste. You’ll be eating the soup every day - as much of it as you want.
In addition, there is a seven day routine of foods to supplement the cabbage soup.
Day One: All the fruit you want (except bananas) along with all the soup that you want. No caffeinated beverages or sodas. Drink only water, tea and cranberry juice.
Day Two: Eat all the vegetables that you want, but avoid dried beans, peas and corn. Eat veggies raw, fresh or cooked. No fats, no sauces, no butter. At dinner, you may have one baked potato with butter - and of course, all the cabbage soup that you want!
Day Three: Eat all the fruits and veggies that you want from day two and day three - but NO baked potato.
Day Four: Bananas and skim milk - yes, all the skim milk you want, plus up to eight bananas, along with - you guessed it, all the cabbage soup you want.
Day Five: Eat ten to twenty ounces of beef (or skinless chicken, or broiled fish). Drink at least 10 glasses of water, and eat up to six fresh tomatoes. (if you substitute for the beef today, you may not tomorrow)
Day Six: Eat all the beef, vegetables and cabbage soup that you want. No baked potato. Lots of leafy green vegetables.
Day Seven: You can have all the unsweetened fruit juices, brown rice, and vegetables that you want - and at least one bowl of soup.

That’s it. Remember - this diet is NOT recommended for long term weight loss, or long term use. It doesn’t contain enough complex carbohydrates to be healthy for longer than a few days. But if you just need a jump-start or a quick fix, it’s a good way to pick up the pace for a week.