In most cases, poor weight gain in preschool and school-age children is the consequence of inadequate dietary nutrient intake relative to metabolic and growth needs. The challenge for the child's clinician is to determine if inadequate dietary intake is the result of an underlying medical problem (organic disease), environmental or psychosocial problems, or a combination of these factors.
This topic will discuss the etiology and approach to poor weight gain in children older than two years. Poor weight gain in children younger than two years and short stature are discussed separately. (See "Failure to thrive (undernutrition) in children younger than two years: Etiology and evaluation" and "Failure to thrive (undernutrition) in children younger than two years: Management" and "Causes of short stature" and "Diagnostic approach to children and adolescents with short stature".)
Nutritional requirements for adolescents and vegetarian children and adolescents are discussed separately. (See "Dietary energy requirements in adolescents" and "Vegetarian diets for children".)
Weight gain follows a predictable course from infancy through adolescence. Height and weight should be assessed routinely and compared with antecedent measurements.
Whenever significant voluntary or involuntary weight loss occurs as described below, or when the rate of weight gain varies from the previously established pattern, there is cause for concern. Any deviation in the pattern of weight gain, when compared with the standardized growth curves from the National Center for Health Statistics (NCHS) (figure 1A-B) should be evaluated.