Past dietary reconstructions are based on a number of approaches that involve
assessment of paleo-environments, analyses of macro- and microplant remains (e.g.,
seeds, pits, pollens, phytoliths, residues from cooking vessels) and animal remains
(e.g., bones, teeth, feathers, coprolites) as well as microbial and stable isotope analyses
of food plants, animals, and hominin remains (Pearsall 2000 ; Reitz and Wing 2008 ).
Stable isotopes of carbon, nitrogen, and strontium found in bone collagen, apatite, and
dental enamel are biomarkers of dietary intake that are widely used in materials found
in archaeological contexts (Tykot 2004 ). Isotopic ratios can provide information on the
types of plants consumed, relative amounts of protein and sources such as marine
versus terrestrial animals. Isotopic biomarkers in teeth provide information on
migration patterns and diet during development (Tykot 2004 ). Recent analyses of fecal
biomarkers indicate that Neandertals from Spain (ca. 50,000 years B.P.) had a diverse
diet with high intakes of meat (high coprostanol proportions) but also significant plant
intake (presence of 5β-stigmastan) (Sistiaga et al. 2014 ). The relative importance of
meat versus plant foods in paleo-diets has not been resolved (Armelogos 2010 ;Milton
2003 ; Ungar 2007 ; Ungar and Sponheimer 2011 ; Ungar and Teaford 2002 )but
contemporary paleo-diet enthusiasts favor diets incorporating substantial amounts of
animal protein (Konner and Eaton 2010 ).
Complex polygenic/environmental interactions were involved in four anatomical
evolutionary trends that have a bearing on contemporary food-related behaviors and
fat storage efficiency. The earliest trend was for increasing body size from the 4
million-year-old australopithecine/paranthropine roots to modern Homo sapiens
(Foley 2011 ; McHenry and Coffing 2000 )(Table10.1). Larger body size requires
more calories and macro- and micronutrients for basal metabolic maintenance, growth,
and repair of tissues, physical activities, and for reproduction in females (Leonard and
Robertson 1992 ; Power and Schulkin 2009 ). Larger size has advantages because
resting energy efficiency increases per unit body size. This relationship is represented
by Kleiber’s law that holds for animals of all sizes: basal metabolic rate (R)is
proportional to the¾power of an animal’smass(M)(PowerandSchulkin 2009 ). The
implications are twofold: (1) larger animals overall need more energy but can utilize
lower energy-dense foods than smaller animals; and (2) larger animals are more
flexible regardingfluctuations in the food supply and energy intake because they can
draw upon larger energy reserves (Power and Schulkin 2009 ). These evolutionary
adaptations in modern food environments of stable, abundant, energy-dense foods
facilitate the accumulation of adipose tissue especially when there are low demands on
adipose energy reserves (Lieberman 2006 ). Table10.1summarizes these hominin
evolutionary trends in body and brain size.
Second, in the Late Pleistocene the movement of hominin populations from the
warm/hot climates of Africa to the colder/temperate climates of Eurasia increased
caloric needs to maintain body temperature and favored stocky torsos (Bergmann’s
rule), shorter limbs (Allen’s rle), and a remodeling of the face (e.g., enlarged
sinuses) and increase in cranial capacity facilitating thermoregulation (Ash and
Gallup 2007 ; Leonard and Katzmarzyk 2010 ; Snodgrass et al. 2009 ). One result
was an increase in the encephalization quotient (EQ) that expresses brain size
relative to body mass (Aiello and Wheeler 1995 ; Armelogos 2010 ).
10 Objective and Subjective Aspects of the Drive to Eat in... 197