In 1994, Professor Jeremy Morris proclaimed physical activity as the "Best Buy in Public Health." More than 20 years later, Americans still aren't buying. Americans today are less active than 50 years ago because the volume of "baseline physical activity" - the physical activity of everyday activities - has declined. Was Dr. Morris wrong? Is physical activity not the "best buy" we thought it was? And if it is, why aren't we buying? What do we need to do to surpass the tipping point where the American public finally begins taking up this “best buy in public health”? To read this full commentary on public health from Dr. Kenneth Powell and the National Physical Activity Plan, please click here.