Cabbage/onion soup diets are mostly used in hospital setting to lose 10-15 pounds before a procedure. There is some validity in detox qualities of the diet, but like some people have already said, it deprives you of a lot of the nutrients that your body needs. If you really want to lose some weight, calorie counting and exercise is the only really surefire way to do it.
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Ibanez uv7bk green dot, Engl fireball 60, genz benz g flex 2x12.