White Castle opened in 1916 as the first fast food restaurant, focusing on hamburgers. McDonald's revolutionized the industry in 1948 through assembly-line production of fast food at high speed and low cost. Studies show that a fast food diet can negatively impact health, as shown in the documentary "Supersize Me" where the subject gained weight and his health declined after a month of eating only fast food. While fast food is inexpensive and tasty, the long term health effects are more serious. Home cooking with fresh ingredients provides more nutrition and fewer calories than fast food, though it takes more time to prepare. The addictive properties of fast food have long been debated.