the prevalence of obesity among U.S. children aged 2-5 years rose from approximately 5 percent in the early 1970s, the period used to establish a baseline for obesity, to 8.4 percent in 2012 (Ogden et al., 2014). As of 2012, approximately one in seven children in this age group was overweight (Fryar et al., 2012). The average 5-year-old girl in the United States weighed 43.2 pounds in 1976-1980 and 46.6 pounds in 2007-2010 (Fryar et al., 2012; Najjar and Rowland, 1987).
• The flavors of the foods children experience beginning in utero and continuing during breastfeeding and complementary feeding establish flavor and food preferences that can persist throughout a lifetime. (Mennella) • The birth of a child is an event that can motivate parents to change long-established behaviors. (Mennella)
Only 10 out of 50 states of USA have obesity rates less than 13%
Human beings are 99.9 percent identical at the genetic level, noted Barkin, yet still have many differences (NHGRI, 2014). Part of the reason for these differences is epigenetics. Barkin defined the science of epigenetics as the study of changes in the expression of genes via post-translational and
post-transcriptional modifications. “Think of it this way,” she said. “You can’t change your genes, but you can change the way your genes behave.”
when the larvae of docile European bees are placed in the hives of the killer bee, the normally placid European bees acquire a phenotype identical to that of killer bees (Dobbs, 2013). “The genes didn’t change, but the expression of the genes did,” said Barkin.
Barkin stated that maternal nutrition also affects the microbiome of mothers and their children—the community of single-celled organisms that live in close association with the body (Peterson et al., 2009). In a study of Japanese macaques, for example, mothers on a Western diet high in fats experienced a shift in microbiome species that affected lipid metabolism and inflammatory response (Friedman, 2015). Exposure to a maternal Western diet appears to pattern the microbiome and effect a pro-inflammatory state in infants (Friedman, 2015; Kumar et al., 2014). Although studies in the past have focused on correlations, many studies currently under way are looking at causation, Barkin reported.
Many chronic illnesses that plague society derive in large part from poor food choices that are dictated by people’s taste preferences,
“We don’t have a problem of children over-consuming broccoli,” she said. “They are over-consuming added sugars and salt, [with] too few fruits and vegetables. This pattern of food choice that is evident in the youngest members of our society mirrors that of our nation’s adults.”
Mennella pointed to two factors that can predispose some children to consume obesogenic diets: inborn, evolutionarily driven taste preferences, and the detrimental consequences of not being exposed to the flavors of healthful foods early in life
In an environment with limited nutrients and abundant poisonous plants, sensory systems evolved to detect and prefer the once rare energy (carbohydrate)-rich and sodium-rich foods that taste sweet and salty and to reject toxic foods that taste bitter
The chemical senses that underlie the flavors of foods and beverages are functioning by at least the second trimester of pregnancy
Taste receptors are found not only in the oral cavity but also in the nasal cavity and in the gut), and activation of these receptors in the mouth can be a source of extreme pleasure or pain. While some responses are inborn (e.g., the liking of sweets, they can be shaped by learning.
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