The Grapefruit Diet By Sondra Forsyth Created in the 1930ΓÇÖs with the misleading claim that grapefruit enzymes boost fat burning. Risks: Malnutrition, photosensitivity, medication interactions. Grapefruit interacts with about 43% of all meds, causing severe effects like arrhythmias, kidney damage, and gastrointestinal bleeding.