The underweight child

The underweight child

How to know if your child is small for their age, or malnourished


Being underweight may be a normal state for some children. But it can also be a major indicator of under-nutrition, placing them at real risk for decreased growth, vitamin/mineral deficiencies and delayed development.  

picture of an underweight child

Why Is My Child Underweight?

Your child could be in a negative energy balance if (s)he does not eat enough food to maintain energy needs, normal metabolism, and daily activities. To prevent your child from being in a negative energy balance, you must first determine her or his energy needs.  Your physician or a registered dietitian can help calculate the calories and specific nutrients your child needs for optimal health.

The Dietary Reference Intakes (DRI) for Americans provides age appropriate guidelines for the amount of calories, protein, calcium and vitamin D needed for each age and gender.  Nutrition4kids has those detailed for your child's age range and for you, if you are pregnant or breastfeeding.

How Will I Know If My Child's Underweight?

Your child's routine visits to the pediatrician or primary provider will likely include measurements of their height and weight. These measurements are then calculated using the Body Mass Index (BMI) or weight for length to determine if your child is underweight. Other measurements can be plotted onto specific growth charts that can show how your child's growth compares with the average sized child of the same sex and age.

Underweight BMI  

Most children will fall between the 5th and 85th percentiles on the BMI or weight for length growth charts. Therefore, if your child is plotted at the 2nd percentile, for example, there could be a concern for them being underweight in terms of their current height.