Brian Leigh Maxwell (1953, London, England – March 19, 2004, San Anselmo, California) was a Canadian athlete, track coach, entrepreneur and philanthropist. He founded PowerBar, a maker of energy and nutritional products for athletes.Maxwell never intended to become a marathon runner and lacked the speed necessary to be competitive at shorter distances. Despite being told as a teenager of his congenital heart condition, he persevered, and by 1977 he was ranked third among all marathoners in the world by Track and Field News. At 51 years of age he died of a heart attack.