ABSTRACT
SHIRIKI KUMANYIKA, WENDELL C. TAYLOR, SONYA A. GRIER, VIKKI LASSITER, KRISTIE J. LANCASTER, CHRISTIAAN B. MORSSINK, and ANDRÉ M. N. RENZAHO
2.1 INTRODUCTION
Obesity is a major risk factor for the development of diabetes, cardiovascular diseases, certain cancers and other chronic conditions that cause disability and premature death and increase costs for health care systems (World Health Organization, 2000 and World Health Organization, 2003). It has taken a place alongside hunger and food insecurity as a major global nutrition concern (Food and Agricultural Organization of the United Nations, 2006). Levels of obesity worldwide show steep trajectories in recent decades (Al-Lawati and Jousilahti, 2004, Barr et al., 2006, Fezeu et al., 2007, Flegal et al., 2010, Katzmarzyk and Mason, 2006, Mbanya et al., 1997, New Zealand Ministry of Health, 2004, Ogden et al., 2010, Organisation for
Economic Co-operation and Development, 2010, Tremblay and Willms, 2000, Wang et al., 2002, World Health Organisation, 2005 and Wu, 2006). These population trends emanate from changes in environmental influences on eating and physical activity: underlying genetic or behavioral predispositions to obesity are more likely to be expressed under environmental conditions characterized by high availability of inexpensively-priced and heavily promoted high-calorie foods, combined with limited demand or opportunity for daily physical activity (Kumanyika et al., 2002 and World Health Organization, 2000). Conditions that predispose individuals to excess caloric consumption are now typical in high-income countries as well as many low-and middle-income countries. Humans are physiologically, socio-culturally, and psychologically geared to eat when food is available, store excess calories as fat, and have poorly developed systems of appetite regulation to prevent overconsumption of calories (World Health Organization, 2000). Hence, weight gain to obese levels reflects normal responses to an abnormal environment.
