The grapefruit diet, also known as the Hollywood Diet and erroneously as the Mayo Clinic Diet, is a short-term fad diet that has existed in the United States since at least the 1930s. . The diet is based on the claim that grapefruit has a fat-burning enzyme or similar property. The variations of the grapefruit diet that are too low in calories (below 1200 calories a day), carbs or essential micronutrients are considered unhealthy and potentially dangerous. While eating half a grapefruit with every meal may be a good way to incorporate more fruit in the diet of a healthy person, grapefruit and grapefruit juice is harmful if the dieter is taking medications that can interact with grapefruit juice or is allergic to citruses.