Before revision: People have promoted the "Okinawa diet", believing it to be nutritionally dense yet low in calories, but it is unlikely that the diet alone could explain high life expectancy among seniors on Okinawa in the 20th century.
After revision: People have promoted the "Okinawa diet", despite the fact that the diet alone is unlikely to solely explain high life expectancy among seniors on Okinawa in the 20th century.