[Page 1422]Failure to thrive (FTT) is the term used to describe an infant or child whose growth rate is significantly below that expected, given his or her age and gender; it can be a result of weight loss in the child or insufficient weight gain as the child develops. FTT is usually defined within the first 2 years of life, although the term can also be used in adult populations to refer to extreme weight loss. The term FTT has more recently been replaced by terms such as growth faltering or weight faltering because of the negative connotations associated with the word failure. FTT itself is not a diagnosis, but it is the result of inadequate caloric intake that may be due to underlying biological, ...