Poor weight gain is a common problem for many children. It’s typically noticed by a parent, caregiver or primary physician who either sees the child isn’t growing well or their weight gain deviates from an expected growth pattern.
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When that weight trend is poor, doctors may consider the child to be “malnourished” or “failing to thrive” in clinical terms.
According to pediatric gastroenterologist Kadakkal Radhakrishnan, MD, your child’s overall trend of weight is often more important than a single drop in their weight. It’s also important for their weight to be compared to height to ensure that the child is gaining weight well in comparison to their height.
This height and weight correlation is plotted using a weight-for-length chart or BMI (body mass index) chart.
“Sometimes toddlers will lose weight as they become more active,” Dr. Radhakrishnan notes. “Their weight may drop in relation to their height but the child can still continue to progress at a normal rate for their age. If there’s a significant drop however in weight within a single measurement, they should be taken to a doctor and re-measured to determine if that drop warrants further action.”
There are many possible reasons a child might not gain the weight they need to stay on track for healthy growth, Dr. Radhakrishnan says. These include:
In 90% of cases children aren’t growing because they’re not consuming enough calories. This can happen when a child isn’t interested in eating due to a variety of reasons or a parent doesn’t understand how many calories their child actually needs.
It can also happen with toddlers who are active and otherwise well but who are less interested in eating.
For infants in their first few months it can be due to an inadequate supply of breast milk or improperly mixing formula.
Occasionally a caregiver with mental health concerns of their own may not adequately feed the child. Or a caregiver may be accidentally mix the formula to be too diluted. Food may also be in short supply for some families.
An older child or teenager may also not eat enough calories because they’re struggling with body image issues due to a possible eating disorder (previously known as anorexia nervosa).
A child may also not eat well if they have oral sensitivity or neurological issues. Such problems may affect their ability to swallow and may be caused by conditions like cerebral palsy or a cleft palate.
Sometimes a child cannot keep formula or food down due to excessive vomiting. This may be due to severe acid reflux or some neurological issues and can cause low muscle tone and a variety of other disorders.
Most infants with acid reflux will likely improve and their growth will continue without issue. But less commonly a younger infant with excessive vomiting may have a narrowing of the outlet of the stomach called pyloric stenosis. This requires a special evaluation that includes an abdominal ultrasound.
A child who can’t properly digest food because their pancreas has poor capacity may also not gain weight well. In this scenario a child may have bulky, frothy, loose, foul smelling and greasy stools as symptoms (as in Cystic Fibrosis).
Disorders that affect the lining of the bowel including celiac disease or Crohn’s disease can also cause children to have poor weight gain. In celiac disease symptoms start when foods that contain gluten are introduced into the diet.
In some situations a child may burn too many calories if they have an overactive thyroid gland.
A child with a heart disorder that leads to heart failure may not eat well if they’re working too hard to breathe.
Rarely, kidney failure or other kidney disorders will affect weight gain (as well as height).
In addition some children may have any of a variety of genetic disorders that can affect weight gain, requiring an evaluation by a specialist.
If you’re concerned your child isn’t gaining the weight they should be or you suspect any of these causes, seek the help of your child’s primary care provider. They’ll need a physical exam where their doctor will look for signs they may not be eating enough calories or for possible medical disorders.
The provider will also be on the look out for fatigue, paleness, thin extremities, loose folds of skin on the arms and thighs and loss of fat over the cheeks.
Your child’s BMI chart may need to be closely monitored and they may need frequent follow-ups and weight checks.
Your provider may also order tests to check for anemia, nutritional status and kidney function. Further tests may be ordered to check for possibilities of celiac disease, Crohn’s disease or a pancreatic enzyme deficiency. Switching to a gluten-free diet will be necessary if a child is diagnosed with celiac disease. Children with pancreatic dysfunction may need digestive enzyme supplements. The provider may also seek the help of an additional specialist like a pediatric gastroenterologist or pediatric dietitian. And the help of specialists should be sought to treat heart problems, Crohn’s disease, thyroid problems or pyloric stenosis.
Most children do require subtle increases in their caloric intake to gain weight. Growth uses up 5 to 10% of a child’s total caloric intake after they’re 6 months old.
“This may require some imagination on the part of a parent or caregiver,” Dr. Radhakrishnan says. Extra calories can be added to their diet for example, in the form of additional oil, sugar or special formulas. A pediatrician or specialist can help with these recommendations.
“Certain medications that stimulate appetite may also help in some cases,” he adds.
If your child continues to not gain weight properly despite getting more calories, your provider may recommend admitting them to the hospital to observe their weight and eating patterns. They’ll receive testing and evaluation by a pediatric dietitian. It’s also possible in some cases supplementary feeding through tubes placed into the stomach through the nose (called naso-gastric feeding) may be needed.
“As with all medical concerns, monitoring and seeking help when situations don’t improve is critical for young children as they grow, so make sure your child gets any care they need right away,” Dr. Radhakrishnan emphasizes.