I have heard of the mystical weight loss property of grapefruit but have never experienced it myself. I am too afraid of sugar to try.
There is nothing wrong with sugar, most things you eat turn into sugar. It's about regulating the intake to provide consistent energy for use rather than to have a few masses of food that the body then turns into fat to store for later. It's POOR NUTRITION that bring about the majority of our obesity issues and most of the problem is connected more to how we eat than what we eat. Nutrition and energy are what regulate the metabolism between anabolic and catabolic modes. You need plenty of calories to lose weight quickly and healthily, you need to break them into smaller more frequent portions though.