Chubby Blair River isn't laughing any more. The 575-pound jokester pitchman for the Heart Attack Grill restaurant has died at the age of 29. The affable River won fans on ads and YouTube as he plugged the tasty virtues of the cholesterol-laden burgers and fries of the cheeky Arizona restaurant that pokes fun at consumer concerns about eating healthy. He apparently died from pneumonia linked to the flu, reports MSNBC. "Cynical people" might find River's death "funny," said Heart Attack Grill owner Jon Brasso. "But people who knew him are crying their eyes out. There is a lot of mourning going on around here. You couldn't have found a better person." Click for more on the grill. (More Heart Attack Grill stories.)