Weight is often the first measurement taken when children visit their healthcare provider. But how important is the number on the scale? Kids are uniquely built with variance in frame, lean muscle, body fat and height — all of which influence body mass. With so many contributing factors, you may feel unsure about what constitutes a healthy weight for your child.
BMI and Health
The Centers for Disease Control and Prevention defines a healthy weight for children older than two as having a body mass index (BMI) between the 5th and 85th percentile for one’s age and sex. BMI is calculated by dividing a person’s weight in kilograms by height in meters-squared. Having a BMI that rests outside of these bounds is often how providers initially consider that a child may be underweight, overweight or obese by medical standards.
But aren’t there limitations to this calculation? Can you be overweight by BMI and still be healthy?
Yes! There are absolutely limitations to a BMI calculation, and you can be overweight on a growth chart and still be healthy. BMI does not account for one’s lean muscle mass or actual body fat. It also does not adequately account for one’s natural frame or body habitus. Despite this, BMI can be an extremely helpful starting point for families and providers in determining the wellness of a child.
A child whose BMI is greater than the 85th percentile may be at risk for weight-related health concerns. If weight is due to excess body fat, and not lean muscle, providers consider checking blood pressure, performing a general physical exam and determining if lab or diagnostic testing would be helpful.
This is not to overmedicalize weight, but rather to better understand a child’s actual health status. Excess body fat can lead to an array of chronic health conditions that not only impact childhood, but also have lasting effects on one’s health as an adult.
In 2007, a study out of the Journal of Pediatrics found that 70 percent of children with a BMI greater than the 85th percentile had at least one risk factor, such as high blood pressure or high cholesterol, for developing cardiovascular disease. High BMI can also lead to a myriad of other health consequences such as type 2 diabetes, sleep apnea, asthma, joint problems, gall bladder disease, gallstones and heartburn.
Maintaining a Healthy Body
In 2016, Adolescent Health, Medicine, and Theory reported that overweight children are victimized more frequently than their healthy-weight peers by stigmatization, bullying and teasing. They also found that children who were clinically overweight reported lower levels of self-esteem and higher rates of depression than those at a healthy weight. Reassuringly, both the physical and psychological consequences of being overweight can be mitigated by dietary changes and increased physical activity. In certain circumstances, especially for children who struggle with binge eating disorders, or those who have been victimized for their weight status, psychological support, such as counseling, can also be helpful.
As many of us know, lifestyle changes involving diet and physical activity can be difficult to maintain. This is especially true for families with limited access to affordable healthy food and safe spaces for their children to play or exercise. Maintaining a healthy body in such circumstances often takes creativity and an exploration of community resources for long-term success.
Decreasing one’s body fat and increasing lean muscle may also be challenging for children of families with a history of obesity. Harvard Health Publishing reports that there are more than 400 genes related to the development of overweight and obesity. Further, if both parents are obese, a child’s likelihood of developing obesity is as high as 80 percent. Despite genetics, committing to healthy lifestyle changes can, and will, overcome one’s familial predisposition. Discussing evidence-based strategies for this with your provider is a great first step toward change.
On the other end of the spectrum, being medically underweight can also have severe health consequences. Children are considered underweight if their BMI is less than the fifth percentile for age and sex on a growth chart. A low BMI generally indicates that children do not have adequate nutrients and/or body fat to meet their physical needs.
Many factors must be considered to tease out the reason for low body fat. Occasionally, being underweight is an indicator of serious physical illness or a chronic condition. Kids with heart disease and severe asthma, for instance, tend to burn calories quickly, which makes it difficult to maintain a healthy weight. Children who have gastrointestinal conditions, such as Crohn’s disease or celiac disease, have a hard time absorbing nutrients that can lead to weight loss and malnutrition. Other children may be underweight simply because they are not consuming enough calories. In early childhood, this tends to be picky eaters. In older children, limited food intake is often related to psychological conditions, such as depression and eating disorders.
Treating Eating Disorders That Lead to Weight Loss
There are many types of eating disorders that lead to weight loss and low BMI. According to the National Eating Disorder Association (NEDA), anorexia nervosa, an eating disorder characterized by restrictive eating patterns, fear of gaining weight and weight loss, is particularly prevalent and dangerous. Those diagnosed with anorexia nervosa have a sixfold increase in mortality compared to mortality rates of the general population. According to NEDA, warning signs of anorexia nervosa, and related eating disorders, include:
* Preoccupation with food, calorie counting and/or dieting.
* Intense fear of gaining weight or becoming “fat,” even when clinically underweight.
* Unusual eating patterns or rituals around food such as cutting food into tiny pieces or pushing food around on the plate/rearranging food without eating it.
* Refusal to eat in public.
* Refusal to eat certain food categories, such as carbohydrates, sugar or fats.
* Denial of hunger.
* Excessive weight loss.
* Excessive exercise/rigidity around exercise.
* Vomiting after eating.
* In biological females, loss of their menstrual period.
* Cold intolerance.
* Dizziness or “passing out.”
* Frequent use of laxatives.
If you have any suspicion that your child is struggling with an eating disorder, an exam by your primary care provider is the best first step toward a diagnosis. At this visit, your provider will talk with you about your concerns, interview your child, obtain vital signs, assess for extraordinary weight changes, perform a comprehensive physical exam, and, oftentimes, obtain bloodwork.
If a child is diagnosed with an eating disorder — but is well enough to receive treatment as an outpatient — routine visits with a nutritionist, counselor, primary care provider, and, when locally available, an eating disorder specialist will play a role in the recovery process.
If a child’s physical exam and/or blood levels are, or become, concerning, hospitalization may be required. Hospitalizations are especially common in treating anorexia. Though stressful for families, inpatient management can be pivotal in jumpstarting, or adjusting, an eating disorder treatment plan and orienting a child toward recovery.
Our bodies, as living beings, require caloric nutrition to thrive. Although the concept is straightforward, many of us and our children struggle to consume an appropriate balance of healthy foods. Whether the issue is under-nutrition, or overeating, the cause is often multifactorial and working toward a change is difficult and often emotionally challenging. This essential work, however, will improve your children’s current health status and put them onto a path toward optimal wellness as adults.
Sarah R. Kiser, CPNP-PC, is a PNP with over a decade of experience in pediatric nursing. She is currently employed at the Dana Hall School, a school-based health center in Massachusetts’s MetroWest.