11 Causes Of Unintentional & Unexplained Weight Loss In Kids

11 Causes Of Unintentional & Unexplained Weight Loss In Kids

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Weight loss is a broad term that encompasses loss of total body mass, i.e., fluid, fat, and muscle mass. It can be intentional or unintentional. Intentional weight loss means planned weight loss under pediatric guidance to manage weight in overweight or obese children. On the other hand, unintentional weight loss in children is abrupt and has hidden reasons.

Most unintentional weight loss causes are temporary, manageable, and seldom adverse. However, if they manifest additional symptoms, such as fever and vomiting, it may indicate some underlying health concern. Knowing the precise cause is vital for timely identification, treatment, and management of the child’s condition.

Read this post to learn different reasons why children lose weight, the symptoms they show, and how to treat or resolve the issue.

Possible Causes Of Unintentional Weight Loss In Children

Weight fluctuations among children are common and mostly benign. If your child loses a few pounds over time, you shouldn’t worry. Rapid development, puberty, and  exam stress could be the reasons for it. However, the list doesn’t end here. There are several other reasons for unexplained weight loss in children (1).

  1. Poor eating habits: Children should eat a well-balanced diet for proper growth, development, and sustenance. When children don’t eat properly or eat fewer calories than required, they lose weight. This condition is temporary and resolves as soon as the child begins eating a calorically optimum, well-balanced diet.
  1. Increased activity: Children indulge in different exercises and activities that increase the energy requirements of the body. If these requirements are not met, the child could experience weight loss. Parents need to consult a qualified nutritionist to ascertain their child’s energy needs and get a suitable diet plan accordingly.
  1. Stressful events: Divorce of parents, school or city change, and bullying at school are some of the stressful life events for children. Chronic stress accompanied by anxiety and depression can bring dietary changes, such as under-eating or loss of appetite, resulting in weight loss. On the other hand, if children indulge in overeating or emotional eating, they can gain weight (2).
  1. Eating disorders: Eating disorders, such as anorexia, are mental health problems that make a child indulge in an overly restrictive eating pattern that causes persistent and severe weight loss. It increases the risk of nutritional deficiencies, leading to further weight loss and growth problems.
  1. Short-term illness: Short-term illnesses, such as the common cold or stomach flu, can make children lose weight. Depending on the infection’s severity, weight loss can be mild or severe. Most children regain their lost weight as soon as their illness is treated and they are able to consume a regular diet.
  1. Oral or neurological issues: Children with oral problems, such as cleft palate and neurological concerns, such as cerebral palsy, can have feeding and swallowing difficulties. These difficulties could reduce their food intake, leading to unintentional weight loss (3).
  1. Gastrointestinal disorders: Gastrointestinal disorders, such as inflammatory bowel disease and celiac disease, often affect proper digestion and food absorption. Besides, they affect a child’s appetite, resulting in unintentional weight loss over time.
  1. Hormonal issues: Hormonal issues, such as Addison’s disease (adrenal insufficiency), hyperthyroidism, and type-1 diabetes, affect an individual’s metabolism, resulting in weight loss. Children with hormonal issues are likely to exhibit additional symptoms, such as abdominal pain, vomiting, and diarrhea, based on the disorder type.
  1. Genetic disorders: Certain genetic disorders, such as cystic fibrosis, could cause unintentional weight loss. Cystic fibrosis features unintentional weight loss despite the child having an excess appetite. Some genetic disorders affect the healthy levels of enzymes in the body, causing muscle and fat loss, leading to weight loss (4) (5).
  1. Medications: Medications for chronic or acute illnesses may cause weight loss as a side effect. If your child is on a certain medication and is losing weight consult your doctor. Anti-epileptic and some anti-depressants are often associated with weight loss (6).
  1. Substance abuse: Teens may indulge in substance abuse, such as narcotics and alcohol. Extended use of these substances could affect the physiological functions and suppress appetite, leading to unexplained weight loss (8).

Besides these conditions, heart and kidney problems could cause unexplained weight loss. Acute or progressive weight loss may also happen due to adverse health conditions, such as cancer. If you suspect your child is losing weight for no apparent reason, consult a pediatrician.

Signs And Symptoms Of Abnormal Weight Loss

Temporary weight fluctuations in children are a common phenomenon. However, they can become a matter of concern when accompanied by additional symptoms, such as (9):

  • General weakness and lethargy
  • Excessive sleepiness or insomnia
  • Loss of appetite
  • Vomiting, diarrhea, or constipation
  • Dehydration and decreased urination
  • Cough and sore throat
  • Abdominal discomfort
  • Fever
  • Dizziness and fainting

Diagnosis Of Unexplained Weight Loss In Children

Ascertaining the precise cause could help treat and manage weight loss in children. Your child’s pediatrician could recommend the following steps (10) (11). 

  1. Physical examination: The doctor will check for physical signs and symptoms of a possible underlying problem. Parents could be asked about the medical and dietary history of the child. The doctor will calculate the child’s body mass index (BMI) and plot it against standard charts, such as CDC’s growth charts. If the child’s weight falls in the lower than the 5th percentile range, they are considered underweight.
  2. Diagnostic tests: The doctor may recommend blood tests, X-rays, and other scans, to determine nutritional deficiencies and determine the cause of unintentional weight loss. 

The doctor may suggest additional tests based on the results of the preliminary tests. If the child is diagnosed with a health condition, they may be referred to a specialist for further assessment and treatment.

Treatment And Management Of Weight Loss In Children

The treatment and management of weight loss will depend on the cause of the condition. Common illnesses, such as flu, causing weight loss can be treated by the primary healthcare provider. Chronic and complex health conditions, such as inflammatory bowel disease, genetic disorders, and hormonal problems, could require long-term care under the supervision of a specialist.

Children with eating disorders and substance addiction may require psychiatric help and other therapies to improve eating habits and lifestyle choices. Treatment or adequate management of the underlying cause usually stops weight loss and lets the child regain lost weight through appropriate dietary supplementation. 

Potential Complication Of Unintentional Weight Loss

Unattended long-term weight loss in children may increase the risk of problems such as chronic fatigue, anemia, and muscle and bone weakness. Depending on the underlying cause and extent of weight loss, the child could also experience nutritional deficiencies. The child may also face psychological issues, such as poor concentration and poor self-image. In extreme cases, it may even lead to developmental delays and regressions.

Weight loss is common in children and is usually temporary. In most cases, eating a healthy, well-balanced diet with an active lifestyle helps the child regain lost weight. However, if your child’s weight loss is persistent or severe, accompanied by additional symptoms, consult a pediatrician to determine the underlying cause and initiate timely treatment. 


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Swati Patwal

Swati Patwal is a clinical nutritionist and toddler mom with over eight years of experience in diverse fields of nutrition. She started her career as a CSR project coordinator for a healthy eating and active lifestyle project catering to school children. Then she worked as a nutrition faculty and clinical nutrition coach in different organizations. Her interest in scientific writing... more