It takes approximately 4 1/2 to 5 1/2 hours to cook a 3- to 4-pound roast in a crock pot on the high setting. A roast of the same size takes 9 to 11 hours to cook in a crock pot on the low setting.
Crock pots are an easy, energy-efficient way to cook less expensive cuts of meat. Meat that is boiled quickly loses a great deal of its flavor; the water forces the juices out of the meat while causing its fibers to contract and become tough. Slow cooking allows meat to retain moisture as the fibers expand, creating meat that is tender and juicy.