Charles Joseph Genster (September 5, 1917 – August 17, 2010) was an American business executive at the nutrition company Mead Johnson who oversaw the development and marketing of Metrecal, a liquid diet drink that became a weight loss craze in the early 1960s. Genster died at age 92 on August 17, 2010, at his home in Princeton, New Jersey. He was survived by four daughters, one son and 10 grandchildren. His wife, the former Barbara Anna Burke, died in 2006.