After years of enduring a poor reputation, fat has been redeemed with new research that suggests fat should actually have a prominent place in your diet. This abrupt about-face has caused significant confusion, especially because the government has long discouraged the intake of fat. Since 1980, when the food pyramid was first introduced, Americans have suffered an explosion of obesity. At least 55 percent of the population is currently considered to be obese, and this number is expected to increase. Chronic diseases associated with an unhealthy diet and lifestyle have also dramatically increased, surpassing infectious diseases as the main cause of death.