rise of overweight and obesity in both youth and adults (Popkin and Gordon-Larson
2004 ). Obesogenic environments are comprised of surroundings, opportunities, and
conditions that promote obesity (Giskes et al. 2011 ; Lake and Townshend 2006 ).
For example, many visible features in the environment influence activity patterns
and food accessibility such as roads and highways, recreational areas, mixed use
residential and commercial neighborhoods, density of fast food restaurants, com-
munity gardens and nighttime lighting (Booth et al. 2005 ; Lake and Townshend
2006 ; McFadden et al. 2014 ; Saelens et al. 2012 ). There are also invisible factors
such as bisphenol A and phthalates used in plastics. Organotins used as pesticides
are classified as obesogens or endocrine disrupting compounds that alter lipid
homeostasis, promote fat storage, disrupt energy balance, and modify the regulation
of appetite (Ahern 2012 ; Holtcamp 2012 ). Obesogens and their metabolites are
most frequently measured in venous and cord blood and urine (Sexton et al. 2013 ).
For example, in one study urinary bisphenol A concentration was an excellent
biomarker showing a dose–response relationship (p= 0.006 for trend test) with
weight >90th percentile in school-age children (Li et al. 2013 ).
This, chapter, however, will focus on the temporally and physicallyproximate
eating environment, those characteristics that trigger and sustain bouts of eating.
Some of these variables are seen, smelled, and tasted; others are seen but not
perceived as influencing food intake and others remain invisible controlling
appetite, ingestion, digestion, absorption, and metabolism (Power and Schulkin
2009 ; Wansink 2010 ). An understanding of the present-day proximate causes of the
recent obesity pandemic requires addressing the evolutionary context in which the
precursors of human obesogenic behaviors and physiology had a selective advan-
tage (Bellisari 2008 ; Cohen and Bernard 2013 ; Wells 2006 ).
Ancestral Environments and the Antecedents to Obesity
Hominin environments varied greatly from African savannahs to European boreal
forests (Bender 2013 ). Geophysical and biological characteristics of each of these
environments presented challenges for survival at every stage of hominin evolution
and were precarious with regard to food sufficiency (Armelogos 2010 ;Turnerand
Thompson 2013 ;Wells 2006 ). If ancestral environments had abundant foods and
variety (i.e., fruits, vegetables,fish, herd animals), they were often only seasonally
available compared to nearly year-round food abundance today. Foods generally had
lower caloric densities, sugar and sodium concentrations, comparable levels of
unsaturated fat, and higher soluble and insolublefiber content than contemporary
processed foods (Armelogos 2010 ; Eaton et al. 1999 ; Konner and Eaton 2010 ).
Among traditional hunters and gatherers, as well as Neolithic agriculturalists, sub-
stantial amounts of time, energy, and even risk could be inherent in obtaining food
compared to foragers today who purchase food at fast food drive-in windows or use a
smart phone to order pizza delivered to their homes (Armelagos et al. 1991 ; Eaton and
Eaton 2003 ; Leonard and Robertson 1992 ; Lieberman 2006 ; Swinburn et al. 2011 ).
196 L.S. Lieberman