Biological Determinants Linking Infant Weight Gain and Child Obesity: Current Knowledge and Future Directions

Abstract

Childhood obesity rates have reached epidemic proportions. Excessive weight gain in infancy is associated with persistence of elevated weight status and later obesity. In this review, we make the case that weight gain in the first 6 mo is especially predictive of later obesity risk due to the metabolic programming that can occur early postpartum. The current state of knowledge regarding the biological determinants of excess infant weight gain is reviewed, with particular focus on infant feeding choice. Potential mechanisms by which different feeding approaches may program the metabolic profile of the infant, causing the link between early weight gain and later obesity are proposed. These mechanisms are likely highly complex and involve synergistic interactions between endocrine effects and factors that alter the inflammatory and oxidative stress status of the infant. Gaps in current knowledge are highlighted. These include a lack of data describing 1) what type of infant body fat distribution may impart risk and 2) how maternal metabolic dysfunction (obesity and/or diabetes) may affect milk composition and exert downstream effects on infant metabolism. Improved understanding and management of these early postnatal determinants of childhood obesity may have great impact on reducing its prevalence.

Infant feeding practices and dietary consumption of US infants and toddlers: National Health and Nutrition Examination Survey (NHANES) 2003–2012

“…Finally, Kerr et al (48) also found that baseline information such as child and maternal BMI, maternal age and education, and child health were the strongest predictors of onset and resolution of obesity in the school years with perinatal, breast-feeding and lifestyle exposures not being predictive. It is possible that early obesity in MexicanAmerican infants and toddlers, which is correlated to higher later obesity (16)(17)(18)(19)(20)(21)(22) , relates more to genetic or parental factors or simply that Mexican-American parents are more prone to under-reporting offering high-energy …”

“…Several studies indicate that rapid weight gain in infancy correlates with obesity in childhood and adulthood (16)(17)(18)(19)(20)(21)(22) . The time of onset and causes of early obesity are uncertain, but one study identified a median 'tipping point' of 22 months for the infant transition to overweight, which decreased to 15 months when adjusted for infants who were overweight by the first physician visit (23) .…”

“…Infant feeding practices hypothesized to be protective against overweight include breast-feeding, delayed introduction of sugar-sweetened beverages, exposure to a wide range of textures and tastes, responsive feeding and appropriate introduction of solid foods (21,(25)(26)(27) . However, there are few studies reporting anthropometric measurements and early feeding practices in children from birth to age 24 months, and they are based on samples which are less ethnically diverse and higher income than the US population (28)(29)(30)(31)(32)(33) .…”

Obesity Prevention in Children from Birth to Age 5

“…Obesity in infants is a controversial topic; however, research supports a link between rapid early infant growth and later obesity. [60][61][62][63] Feeding. There are concerns with diagnosing obesity in infancy because of the unintended consequence of a mother's restricting food intake during infancy; restriction of fat intake can adversely impact brain development.…”

Bottle Size and Weight Gain in Formula-Fed Infants

“…This period conveyed significantly more risk than weight gain between 0 and 2 months, and between 4 and 6 months, suggesting that 2 to 4 months may be an especially critical period for differences in weight trajectory on later obesity. 32 Ultimately, whether these differences in weight and weight-for-length persist to influence BMI later in childhood needs to be determined.…”