What Is It?The grapefruit diet is a protein-rich meal plan that focuses on consuming grapefruit or grapefruit juice at every meal. The diet's goal is quick weight loss, and it's a 12-day plan. While several versions of the diet exist, the majority of them include a daily caloric intake of less than 1,000 calories.Under the guidelines of the diet, the foods can be prepared with any amount of spices, salad dressings, or butter. Some caveats of the diet include no extremely hot or extremely cold