Автор посмотрите:http://www.uptodate.com/contents/patient-information-poor-weight-gain-in-infants-and-childrenПеречисляются причины, по которым дети могу плохо есть и набирать вес:Prenatal — Small for age at birth (called intrauterine growth restriction);prematurity; prenatal infection, birth defects; exposure to medications/toxins that limit growth during pregnancy (eg, anticonvulsants,alcohol).# Neonatal (<1 month)—Poor quality of suck,incorrect formula preparation; breastfeeding problems; inadequate number of feedings; poor feeding interactions (eg, infant gags or vomits during feedings and parent assumes child is full); neglect; birth defects that affect the child's ability to eat or digest normally# Three to six months — Underfeeding (sometimes associated with poverty or not understanding dietary needs of infants); improper formula preparation; milk protein intolerance; problems with child's mouth/throat; medical problems that affect absorption of nutrients (celiac disease; cystic fibrosis); medical problems that increase the number of calories needed (congenital heart disease), gastroesophageal reflux.