Reducing Societal Obesity: Establishing a Separate Exercise Model through Studies of Group Behavior

Figure 2

The growth of world population and some major events in the history of technology. Sources: Cipolla 1974; Clark 1961; Fagan 1977; McNeill 1971; Piggott 1965; Derry and Williams 1960; Trewartha 1969. See also Allen 1992, 1994; Slicher van Bath 1963; Wrigley 1987 [22, p. 22].