Brian Maxwell was an elite marathoner in the 1970s, achieving third place in the world marathon rankings in 1977. Maxwell had encountered stomach cramping and problems in the later stages of marathons and he decided to seek a solution. Maxwell knew that at approximately 21 mi (34 km) into a marathon, the point in a race well known to marathoners as "the wall," the body's carbohydrate sources are severely depleted. Maxwell's wife Jennifer was a trained nutritionist, and together they sought to create an energy source that an endurance athlete could consume before, during, and after races and training sessions to assist the body in its recovery from the depletion of its energy stores. Maxwell had initially thought that with his years of racing experience and his wife's nutritional knowledge, their ideas could simply be sold to a large food products company; no organizations expressed interest in Maxwell's ideas for an energy bar.
The original formulation of the PowerBar was developed in the Maxwell's kitchen at their home in California in 1986. The bar was designed as a high carbohydrate, low fat energy source, made entirely of natural ingredients. It was determined by testing both elite level racers and more recreational runners that a PowerBar was best consumed with water. Maxwell later developed a companion PowerBar gel that was easier to ingest if the athlete was in motion. One of the chief attractions of the PowerBar and its gel formulation was its portability and its convenience.
The PowerBar was initially sold on site at races and by mail order. It proved to be one of the most remarkably successful athletic supplements ever created. With the sustained fitness boom of the late 1980s and early 1990s producing record numbers of runners and triathletes, there was a fertile ground for the growth of the PowerBar market. Once Maxwell had established a market for the PowerBar, a significant number of competitors created their versions of sports energy bars. PowerBar also established itself with non-athletes as a healthy alternative snack food. Maxwell sold PowerBar to the Nestle company in 2000 for a reported $375 million dollars.
Maxwell, the former marathoner and health food innovator, died of a heart attack in 2004 at age 51.