When considering weight loss, consider the possibility of an error in recorded weights.
Obtain a thorough dietary history. Consider inaccuracy, especially if an eating disorder is possible.
A basic workup should be performed before attributing the loss to mental health. Consider the following assessments: complete blood cell count, comprehensive metabolic panel, C-reactive protein, erythrocyte sedimentation rate, tuberculin test, rapid plasma reagin test, HIV test, tissue transglutaminase plus immunoglobulin A, thyrotropin plus free thyroxine, stool guaiac test/culture/ova/parasites, and urinalysis.
Close follow-up is mandatory. Admission criteria if an eating disorder is considered can include less than 75% of the ideal body weight, a supine heart rate less than 50 beats/min, a temperature less than 35.6°C, a systolic blood pressure less than 90 mm Hg, arrhythmia, and orthostatic vital signs.
If findings from the workup are negative, attempts to increase caloric intake are insufficient, and an eating disorder is not suspected, refer the patient to a registered dietitian and/or a gastroenterologist.
Reviewed and updated on November 6, 2020 by Benjamin Levinson, MD
The definition of significant weight loss varies by the child’s age and includes acute and chronic causes.
Clinically significant weight loss depends on age.
Newborns may lose 5% to 10% of their birth weight in the first few days after birth; losses greater than 12% are concerning.
In children, unintentional weight loss greater than 5% from baseline may be concerning.
In adolescents, in addition to weight relative to baseline, consider body mass index (BMI) percentile.
In adolescents, planned dieting must be distinguished from an eating disorder, such as anorexia nervosa or bulimia nervosa.
Of female adolescents, 0.5% have anorexia nervosa.
1% to 5% meet criteria for bulimia nervosa.
5% to 10% of all eating disorders occur in boys.
As many as one-half of adolescents with disordered eating do not meet the Diagnostic and Statistical Manual of Mental Disorders criteria.
These individuals remain at risk for developing both physical and psychological complications from their altered eating habits.
In general, weight loss occurs when caloric intake does not meet caloric expenditure.
In breastfed infants, actual intake may be difficult to ascertain, given dependencies on both maternal milk production and effective feeding.
In children, even if enteral intake seems sufficient, there may be issues with absorption and ability to metabolize the nutrition.
Weight loss may result from excessive fluid losses.
For all patients, records of previous body weights, allowing for differences in weighing technique, can be helpful.
Obtain a complete history, including
Diet and consumption history of child and family, with caloric assessment.
Assess parental expectations.
Obtain a careful birth, family, past medical, and medication history.
Assess sick contacts/exposure to illnesses and immediate history of febrile or other illnesses.
Determine the number of urinations and bowel movements per day.
Review gastrointestinal/malabsorption symptoms, such as vomiting, constipation, and diarrhea, and amount, frequency, and character of stools.
Assess other indications of feeding intolerance, including rashes.
Compare caloric intake with estimated caloric needs.
In general, an infant should gain 25 to 30 g each day in the first 3 months after birth.
Assess feeding effort and coordination.
If the infant is formula-feeding,
Discuss the proportions in which formula is constituted.
Estimate total caloric intake from the volume of formula and caloric density of formula (standard is 20 kcal/oz).
If the infant is breastfeeding, assess
Perceived adequacy of maternal milk production.
Ability of infant to breastfeed.
Typically, birth weight is regained in 14 days; consider interventions if it is unlikely to be regained in the first 3 weeks, especially with new parents.
For children and adolescents,
Discuss whether eating leads to symptoms, such as pain, vomiting, diarrhea, or fatigue.
Discuss quantity and type of stools.
Assess body image, social context (including family function and patient’s emotional well being), and stressors.
Consider HEEADSSS (home environment, education and employment, eating, peer-related activities, drugs, sexuality, suicide/depression, safety) examination
Does the patient participate in sports in which weight loss is a goal?
Such as wrestling, gymnastics, ice-skating, running, swimming,diving, and dancing.
If yes, obtain a thorough dietary and supplement history.
For girls, obtain a menstruation history.
Subjective impressions of weight loss should be verified objectively before an evaluation is undertaken.
True weight loss may sometimes be difficult to differentiate from factitious weight loss.
Errors occur in the recorded weight of 5% to 20% of all children because of faulty equipment or poor technique.
Weigh the patient and plot that weight onto a growth chart; consider serial weight measurements for computing growth velocity.
Consider weighing a breastfed infant before and after a feeding.
For children 2 years and older, compute BMI and BMI percentile.
For vital signs,
Assess temperature, supine heart rate (HR) (if an eating disorder is possible), blood pressure (BP), and orthostatic vital signs.
For physical examination,
Assess mental status.
Assess volume status and for anemia (eg, pale conjunctivae).
Examine oral mucosa for thrush and ulcerations.
Oral aphthous ulcers may be related to Crohn’s disease.
Discoloration of teeth may be related to purging behaviors.
Assess cardiorespiratory status.
Assess abdomen and for organomegaly.
Look for signs of malnutrition or vitamin deficiencies (eg, lanugo).
Assess for toxidromes in adolescents.
In breastfed infants, in which weight loss is suspected because of inadequacy of feeding, observe the mother breastfeeding the baby.
The differential diagnosis for weight loss is broad and varies somewhat with age.
Of note, poverty is the greatest single risk factor for developing failure to thrive in the United States.
Psychosocial factors (eg, poor parent-child interaction, depression, rumination) often underlie poor growth and development.
Actual weight loss is much less common in this setting than slowdown or cessation of weight gain and linear growth.
Psychosocial dysfunction resulting in a child’s weight loss requires a prompt and thorough evaluation.
Eating disorders have been described in prepubertal children as young as 7 years.
Newborns and young infants
Difficulties in establishing breastfeeding
Inappropriate dilution or choice of formula
In breastfed infants, inadequate intake at the breast is the most common reason for weight loss.
In formula-fed infants, consider unsuccessful feeding related to parental inexperience; if this is not the case,
Search for an organic problem.
Evaluate family dynamics, support mechanisms, and adjustment to the newborn.
Excessive losses from vomiting and/or diarrhea
With vomiting, consider gastrointestinal malformations (eg, pyloric stenosis, duodenal atresia).
Central nervous system (CNS) dysfunction
Somnolence from maternal medications/substance use disorder
Maternal depression, inexperience, or lack of knowledge
Polyuria (ie, diabetes insipidus, renal disease)
Older infants, preschoolers, and school-aged children
Psychosocial dysfunction (“failure to thrive”)
Loss of appetite
Acute (eg, otitis media)
Chronic (eg, malignancy)
Childhood eating disorder
Poor utilization (eg, malabsorption syndromes)
Fever and infection
Chronic illness (eg, congenital heart disease)
Chronic illness with compound mechanisms
Inflammatory bowel disease
Immunodeficiency disorders, especially HIV infection
Adolescent eating disorders
Suspect when the adolescent is unwilling or unable to maintain body weight over a minimally normal weight for age and height.
Attitudes and behaviors about eating or body image are distorted; amenorrhea, emaciation, and overactivity may be described.
Concurrently, may have hypothyroidism, bradycardia, hypothermia, growth of lanugo-like hair on body and extremities.
Binge eating, followed by self-induced vomiting, self-starvation, overactivity, and use of cathartics or diuretics to reduce weight
These behaviors are practiced in secret, and the adolescent often denies them.
Other eating disorders
Psychiatric affective disorders, especially depression
Malignancy, especially lymphoma
Inflammatory bowel disease
Sports-related weight loss
Adolescents may engage in unhealthy weight-control practices to seek advantage in their athletic activities.
These may include food restriction, vomiting, overexercise, diet pills, stimulants, insulin, nicotine, and voluntary dehydration.
Evaluation is guided by clinical suspicion.
For infants, ensure that a newborn screening has been performed.
Studies may include:
Comprehensive metabolic panel
Complete blood cell count, blood smear
Erythrocyte sedimentation rate, C-reactive protein
Tuberculin test, rapid plasma reagin, HIV test
Tissue transglutaminase plus immunoglobulin A
Thyrotropin plus free thyroxine
Stool guaiac test/fat/culture/ova/parasites
Urinalysis, including specific gravity; urine culture
Imaging is guided by clinical suspicion.
Diagnostic procedures may be performed as guided by clinical suspicion.
Upper endoscopy with biopsy
Sweat test (for chloride)
Esophageal motility testing
In addition to diagnostic testing, serial evaluations of weight and intake are the cornerstones of assessing weight issues.
In breastfed infants with inadequate weight gain, support and education are appropriate interventions.
Appropriate weight gain in the following few days provides evidence that the infant is well and confirms the diagnosis of initial underfeeding.
Prematurely recommending discontinuation of breastfeeding is inappropriate.
The mother’s motivation to breastfeed and her positive or negative feelings about the experience should be discussed.
Encouragement and support should be given for continued breastfeeding.
Do not reinforce parental perceptions that the mother’s milk supply is insufficient or less nutritious than formula.
Lactation consultants or community organizations (eg, La Leche League) may be helpful in supporting lactation efforts.
Infants who fail to thrive while breastfeeding require more intensive nutritional rehabilitation, while breastfeeding is still preserved.
If, however, the situation requires supplemental formula, counsel the family that this formula will not negate the positive benefits of human milk and should be used only for a short time (ie, until the next weight check), while they are awaiting milk supply and/or breastfeeding to improve. Supplemental formula should be provided only after breastfeeding.
For admission criteria, see When to Admit below.
Obtain urine for a dipstick urinalysis to be performed in the office if this type of analysis is available.
Perform the workup indicated above, plus any additional workup that seems indicated.
Obtain a dietary history.
If findings from the dietary history indicate insufficient caloric consumption and there are no concerns for eating disorders (ie, a patient who had no issues with weight previously, in whom a stimulant was started for attention-deficit/hyperactivity disorder, and who is now not eating much), provide guidance regarding how to increase this consumption. Simple tips include
By using a blender, create a weight-gainer shake with milk, peanut butter, fruit, and ice cream. (The child can try different ingredients/recipes until they create one that is palatable.) Then drink this shake after meals.
Add olive oil or extra cheese to foods.
Parents, allow more judicious use of snacks/desserts after eating a nutritious meal.
For kids who typically graze throughout the day, switching to 3 meals plus 2 snacks daily can be helpful.
If needed, start consuming PediaSure or Ensure after meals (if picky eating has led to weight loss, though, this approach can exacerbate the picky eating).
When to Refer
Refer when there is evidence of or suspected
Endocrinopathy (ie, thyroid, adrenal, pituitary)
Gastrointestinal disorder (eg, gastroesophageal reflux disease; malabsorption, including cystic fibrosis; inflammatory bowel disease; celiac disease)
Surgical abdominal problem (eg, pyloric stenosis, Hirschsprung disease, volvulus)
Psychiatric diagnosis in child or caregiver
Concern for eating disorder in the child or adolescent
If findings from the workup are negative and insufficient caloric intake is still suspected, refer to a registered dietitian and/or a gastroenterologist.
When to Admit
A newborn, when
Weight loss cannot be managed in the outpatient setting.
Weight loss is greater than 12% to 15% of birth weight.
Excessive fluid loss (from vomiting, diarrhea, or polyuria).
Evidence of infant hypernatremic dehydration.
Suspected infection, metabolic abnormality, congenital heart disease, or other conditions requiring evaluation.
Extreme passivity of the infant, which may require tube feeding.
Need for intensive maternal education and support.
At any age, when
Weight loss is excessive (>5%–10% of previous weight).
New-onset diabetes mellitus (usually).
Evidence of severe febrile illness (eg, pneumonia, pyelonephritis, osteomyelitis, meningitis, septic arthritis).
Evidence of dehydration.
Electrolyte abnormalities (eg, hypernatremia, hypokalemia).
Evidence of significant psychosocial dysfunction.
An adolescent, when
Eating disorder cannot be managed in the outpatient setting.
Severe malnutrition, with weight less than 75% of ideal body weight.
Supine HR less than 50 beats/min while adolescent is awake (<45 beats/min while adolescent is sleeping).
Temperature less than 35.6°C.
Systolic BP less than 90 mm Hg.
Orthostatic vital signs (BP >10 mm Hg or pulse >20 beats/min).
Given that many adolescents have orthostatic vital signs, not all centers follow this guidance; please consult the center adolescent medicine team.
Evidence of dehydration or electrolyte abnormalities.
Acute food refusal.
Uncontrollable binge eating and purging.
Acute medical complication of malnutrition (ie, syncope, seizures, cardiac failure, pancreatitis).
Suicidal intent or ideation, or psychosis.