by Laura Collins Lyster-Mensh and Lori Lieberman
(We promise it looks harder than it is!)
Can you play Tic-Tac-Toe? If so: you can fill out and understand a growth chart.
Parents, you may need to do this yourself if your loved one has an eating disorder. If you are waiting for your first eating disorder specialist appointment or your loved one’s physician has not charted and explained your loved one’s lifetime growth chart, you can do so yourself.
Why? Because each young person’s growth chart is, and should be, unique.
This may surprise you, but NONE of the following will tell you if a person is malnourished:
- Looking at them.
- Their weight.
- BMI (Body Mass Index)
- Someone else’s weight at the same age or height.
- Comparing to the person’s weight or height a month ago
There is a better way: plotting weight and height and age in the chart for their sex over time to see if their individual growth has gone off track. It’s called a “BMI for Age” chart, and if your physician has not plotted it for you, we recommend you do it yourself. (If you can get it from your doctor, skip the “how” and go on to the why.)
CREATING A BMI FOR AGE CHART
Gather all the weights and heights you know, and at what age, since early childhood. You don’t need every one taken: just use what you have, and try to include at least one a year or so. The more “points” the better!
Go to this page: https://nccd.cdc.gov/dnpabmi/calculator.aspx
Write down the BMI percentile for each date you have, using that calculator.
Now, download and print a chart for BOYS or GIRLS. Put the points in on the boy or girl chart by starting at the bottom and choosing the age, then put a dot above that age for the BMI percentile number you calculated online. Easy!
Now for the magic: draw a line to connect all the dots!
NOW you have important information!
How to interpret the line you’ve drawn:
You’ll notice that the chart had several lines already drawn on it. They all do a similar thing: they rise steadily each year and then more slowly during the late teens and early 20s. This is normal and expected. Most young people’s unique line will roughly follow one of these lines and not cross over or start following another. These lines are the expected growth curves for your unique person.
It is expected that most people will remain around the same line as they grow. None of the lines is better or worse than another, nor is one healthier than another. What is normal and indicates health is when someone stays on the same general pattern as they grow.
If, for example, your loved one’s line, or “growth curve,” is similar to the one at the top (the one that says “90” at the end) then they will usually stay on or around that line. If that person’s line drops into the 80 or the 70 lines this means they may be malnourished.
Some people’s growth curves are average and stay at or around the line that reads “50” at the end. “Normal” for that person will be to stay at or near that line. If your loved one’s unique line changes from the 50 and goes down to the 40 or 30 that may mean THEY are undernourished.
The same is true for someone who has always been on, or “tracked” normally on the 30 line.
The key to remember is that when an individual stops developing the way their unique genetic growth pattern is meant to go then it may be that they are not getting enough nutrition and this is changing their growth. These changes, where someone’s chart stops following their unique line, may be a sign of serious illness: an eating disorder or another growth-changing illness.
There is no “average” BMI that all people can or should be or strive for. But failing to grow as normal for that individual SHOULD be seen as a health problem. Although some people, some insurance companies, and even some research, sets BMI numbers or weights at one number for all patients, it is crucial that you know what is normal for YOUR loved one and are alert to the signs that something is amiss.
You may need to advocate for your son or daughter to make sure everyone on his or her treatment team knows what is normal for them. If your child was normally on any of the lines above the 50 line, you may have to advocate even more firmly, as not all clinicians – even pediatricians – are aware that going “off the growth curve” can be an early sign of serious mental illness. Not all health professionals know that it is healthy and normal to stay on one’s genetic and personal growth curve: not to conform to averages.
Growth charts can be helpful tools in seeing if an individual may be ill, but they are only one of many tools to use. Experts in eating disorders are expected to be skilled in a range of such tools.
A note on language
Terms like “starving” and “overweight” are equally unhelpful. Each unique body has unique nutritional needs and genetics.
Special thanks to Lori Lieberman, RD, MPH, CDE, LDN loriliebermanandassociates.com for her collaboration on this article!