Developmental origins of obesity: early feeding environments, infant growth, and the intestinal microbiome.

OBJECTIVES Pediatric overweight and obesity are growing problems worldwide, with increasing prevalence among even infants and young children. The refractory nature of early overweight necessitates identifying the factors contributing to early excess weight gain for successful intervention. Early feeding practices may be particularly important in shaping long-term vulnerability to obesity. How and what infants are fed can influence weight gain, adiposity, and energy metabolism during infancy and across the life course through a number of interacting physiological and behavioral pathways. This article argues that these biological mechanisms interact with the social and behavioral context of infant feeding to create differential vulnerability to later obesity. METHODS This article reviews recent research on the potential mechanisms linking infant feeding and risk of later obesity, focusing on the emerging role of microflora colonization. RESULTS The nutritive and non-nutritive components of breastmilk, formula and solid foods and the practices surrounding feeding shape the infant metabolome, programming growth rates and body composition, altering metabolism and physiology, promoting differential microfloral colonization, and shaping behavioral responses to foods and eating. CONCLUSION The occurrence of chronic disease precursors at increasingly younger ages and the tendency of overweight young children to become overweight adolescents and adults underscore the importance of understanding this complex early exposure and intervening early to prevent the development of obesity in increasingly weight-promoting environments.