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Obesity is fundamentally a condition where physiology and behavior of individuals meet the environment, and the emerging global obesity pandemic reflects the contribution of a wide range of cultural, societal, economic and systemic driving forces. Today, different areas of obesity research are relatively separated from each other in discrete silos, with biomedical research determining most of our understanding and solution strategies. This has led to the Y in the road, which means the questionable assumption that effective drug treatment of individual patients is also an effective measure to improve population health. Since human obesity is a condition of population health and planetary impact a better integration of biomedical and public health approaches is based on critical (self-)reflection and communicative understanding of scientists from various research areas who should be on an equal footing. [ABSTRACT FROM AUTHOR]

The WHO has developed new growth curves based on breast-fed infants. Recommendations for energy intake have been adopted based on measurements of total energy expenditure. Data on human milk (HM) intake are needed to estimate the energy intake from this food source. However, objective HM data from around the world have not been available, because these measurements are difficult to obtain. Stable isotope methods have been developed to provide objective measurements over a 14-d period. A pooled analysis of 1115 data points of HM intake, obtained using the dose to the mother deuterium oxide turnover method, was undertaken in infants aged 0-24 mo from 12 countries across 5 continents. A hierarchical model was needed to estimate mean HM intake and its variance within and between countries given the complexity of the data. The overall mean HM intake was 0.78 (95% CI = 0.72, 0.84) kg/d, and the age-specific estimates indicated that intake increased over the first 3-4 mo and remained above 0.80 kg/d until 6-7 mo. The variability of intake increased in late infancy. Boys consumed 0.05 kg/d more than girls (P < 0.01). HM intake was strongly, inversely associated with non-HM water intake [r = -0.448 (95% CI -0.511 to -0.385); P < 0.0001]. These objective isotope values of HM intake improve our understanding of the magnitude and variability of HM intake within and across populations and help to estimate nutrient intakes in breast-fed infants. J. Nutr. 140: 2227-2232, 2010. doi: 10.3945/jn.110.123489.

ABSTRACT Background Early menarche tends to be preceded by rapid infancy weight gain and is associated with increased childhood and adult obesity risk. As age at menarche is a heritable [...]

Hominin evolutionary history is characterized by regular dispersals, cycles of colonization, and entry into novel environments. This article considers the relationship between such colonizing capacity and hominin biology. In general, colonizing strategy favors rapid rates of reproduction and generalized rather than specialized biology. Physiological viability across diverse environments favors a high degree of phenotypic plasticity, which buffers the genome from selective pressures. Colonizing also favors the capacity to access and process information about environmental variability. We propose that early hominin adaptive radiations were based upon the development of such capacities as adaptations to unstable Plioeene environments. These components came together, along with fundamental changes in morphology, behavior, and cognition in the genus Homo, who exploited them in subsequent wider dispersals. Middle Pleistocene hominins and modern humans also show development of further traits, which correspond with successful probing of, and dispersals into, stressful environments. These traits have their precursors in primate or ape biology, but have become more pronounced during hominin evolution. First, short interbirth intervals and slow childhood growth allow human females to provision several offspring simultaneously, increasing the rate of reproduction in favorable conditions. This allows rapid recovery from population crashes, or rapid population growth in new habitats. Second, despite high geographical phenotypic variability, humans have high genetic unity. This is achieved by a variety of levels of plasticity, including physiology, behavior, and technology, which reduce the need to commit to genetic adaptation. Hominin behavior may increasingly have shaped both the ecological niches occupied and the selective pressures acting back on the genome. Such selective pressures may have been exacerbated by population dynamics, predicted to both derive from, and favor, the colonizing strategy. Exposure to ecological variability is likely to have generated particular selective pressures on female biology, favoring increasing steering of offspring ontogeny by maternal phenotype. We propose that the concept of hominins as 'colonizing apes' offers a novel unified model for interpreting the suite of traits characteristic of our genus. KEY WORDS adaptation; plasticity; human evolution; migration; dispersal DOI 10.1002/ajpa.20735

Energy intake recommendations for infants are based on data from industrialized countries. FAO/WHO/UNU expressed the need for studies on total energy expenditure (TEE) and basal metabolic rate from developing countries covering current and changing lifestyles. For this observational study, 65 infants of differing socioeconomic status (SES) (n = 32 middle SES, n = 33 low SES) were selected in Pelotas, southern Brazil, aiming to: 1) compare TEE, minimum observable energy expenditure (MOEE), activity energy expenditure (AEE) between breast-fed infants 8.7 mo of age from middle and low SES; and 2) investigate the effect of potential mediating factors on TEE and AEE. TEE and total body water were measured with doubly labeled water, MOEE with respiration calorimetry, breast milk intake using the dose-to-the-mother deuterium-oxide turnover method, food intake using 1-d food weighing, and prevalence of overweight using BMI Z-scores. TEE adjusted for ethnicity was 257 (95% CI 232-281) kJ/(kg * d) in middle SES infants vs. 318 (95% CI 294-342) kJ/(kg, d) in low SES infants (P 0.001). MOEE did not differ between groups and the difference in TEE was therefore attributed to AEE (P = 0.008). The effect of SES on AEE was mediated by the number of persons per bedroom (crowding). Prevalence of overweight tended to be higher in middle SES infants (P = 0.054) than in low SES infants. The difference in TEE and AEE between SES groups emphasizes the importance of an accurate description of the SES of any population in which TEE is studied and questions the extent to which TEE data from middle-class infants in transitional countries should be considered normative.

Although it is widely accepted that energy expenditure in infants is a function of feeding pattern, the mechanism behind this is not well understood. The objectives of this observational study were as follows: 1) to compare minimal observable energy expenditure (MOEE) between 2 subgroups of breast-fed infants, a BM group in which breast milk was the only source of milk and a BCM group given cow's milk in addition to breast milk; and 2) to identify potential mediators of a feeding pattern effect. For this purpose, infants were classified by feeding group on the basis of a mother's recall. Respiration calorimetry was used to measure MOEE in 62 infants (n = 35 BM, n = 27 BCM) aged 8.7 mo in Pelotas, southern Brazil. Breast-milk intake was measured using deuterium oxide, complementary food intake by 1-d food weighing, total energy expenditure and total body water using doubly labeled water; anthropometric indices were calculated. MOEE was 1672 [+ or -] 175 kJ/d in BM compared with 1858 [+ or -] 210 kJ/d in BCM infants (P < 0.001). Mass-specific MOEE was 201 [+ or -] 24.6 and 216 [+ or -] 31.9 kJ/(kg * d) in BM and BCM infants, respectively (P = 0.041). MOEE (kJ/d) was mediated by protein intake and fat-free mass ([R.sup.2] = 41.4%). We conclude that complementary feeding with cow's milk alters the sleeping metabolic rate in breast-fed infants. These findings deserve attention in relation to 'metabolic programming' and the development of obesity later in life. J. Nutr. 135: 1889-1895, 2005. KEY WORDS: * minimal observable energy expenditure * sleeping metabolic rate * breast milk * cow's milk * infants

Studies have shown that after controlling for the effects of body size on brain size, the brains of adult humans, rhesus monkeys, and chimpanzees differ in relative size, where males have a greater volume of cerebral tissue than females. We assess whether head circumference sexual dimorphism is present during early development by evaluating sex differences in relative head circumference in living fetuses and infants within the first year of life. Head circumference is used as a proxy for brain size in the fetus and infant. Femur length is used as a proxy for body length in the fetus. Ultrasonography was used to obtain fetal measures, and anthropometry was used to obtain postnatal measures in humans, rhesus monkeys, baboons, and common marmosets. We show that statistically significant but low levels of head circumference sexual dimorphism are present in humans, rhesus monkeys, and baboons in early life. On average, males have head circumferences about 2% larger than females of comparable femur/body length in humans, rhesus monkeys, and baboons. No evidence for head circumference sexual dimorphism in the common marmoset was found. Dimorphism was present across all body size ranges. We suggest that head circumference sexual dimorphism emerges largely postnatally and increases throughout maturation, particularly in humans who reach adult dimorphism values greater than the monkeys. We suggest that brain dimorphism is not likely to impose an additional energetic burden to the gestating or lactating mother. Finally, some of the problems with ascribing functional significance to brain size sexual dimorphism are discussed, and the energetic implications for brain size sexual dimorphism in infancy are assessed. KEY WORDS human; rhesus monkey; baboon; marmoset; encephalization

Low birth weight, a major cause of infant morbidity and mortality, is caused by different factors in Western and developing-country populations. In addition to differing in terms of ethnicity, maternal size, maternal nutritional status, and disease load, developing-country and Western populations are also characterized by different environmental heat loads. Thermodynamic theory predicts that heat stress is mitigated by reduced size of both mother and offspring, and therefore generates the hypothesis that reduced birth weight may be an adaptation to environmental heat load. The aim of this study was to test the hypothesis that environmental heat load is associated with between-population variability in birth weight. Data on birth weight and thermal environment were obtained from the literature for 140 populations. Further data on several physical, social, and biological confounders were also collated. After adjusting for confounding factors, of which only maternal height and per capita gross domestic product were statistically significant, heat stress showed a significant inverse relationship with birth weight in 108 populations, accounting for an additional 9.6% of the between-population variance. Though based on data collected from more than one source, these results are consistent with the hypothesis that heat stress is inversely associated with birth weight, as previously reported for within-population studies. Further studies are needed to establish to what extent heat stress is a determinant of low birth weight in developing countries. KEY WORDS temperature; thermoregulation; fetal growth