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How to Help My Underweight Child Grow


This post is sponsored by Healthy Height. We received product from Healthy Height to review and we loved it. The links to Healthy Height in this post contain affiliate links. If you purchase something through these links, we receive a small commission at no extra charge to you.


Happy toddler boy playing with toys

What Does “Underweight” Mean for My Child?


When your child is classified as “underweight” it means that their body-mass-index (BMI) is less than the 5th percentile. BMI is a way to compare weight to height to ensure that a child is growing proportionally. Being at the 5th percentile means that 95% of other same-sex, same-age, children would have a higher BMI (and only 5% would have a lower BMI).



Family of four laughing together

The Concern with An Underweight Child


Your child’s growth is primarily driven by their genetic potential (how their parent’s body is built) and their nutritional profile (what they consume). Rarely do they have an undiagnosed endocrine disorder that is limiting their growth, and usually these rare conditions present with poor linear (height) growth rather than just poor weight gain and low BMI. That means that if both parents were thin, then the child is much more likely to be thin, and vice versa.


You are probably asking whether it matters if your child has a low BMI. Being underweight has been shown to increase the risk of “fair or poor'' health, according to caregiver assessment surveys. In addition, in some studies children who are underweight had a higher rate of hospitalization and slightly higher rate of developmental concerns. Clearly, socio economic issues are at play here, as children who live in poverty often struggle to get the necessary nutrition to gain weight appropriately, but they also may struggle to access medical care and even struggle to get assistance with development and academics.


In addition, there is a slight risk of bone health problems when a person remains underweight for long periods of time. Since they do not carry as much weight, there is less daily stress on their bones, which in turns limits the amount of healthy natural bone turnover and regrowth, which sometimes leads to a higher risk of osteopenia or osteoporosis in their elderly years, especially in women.


For these reasons, growth metrics are a big part of routine pediatric preventative health care. And when your child’s pediatrician tells you that they are underweight, these are the concerns they are thinking about and hoping to prevent.



Doctor listening to child's heart with stethoscope

What Can I Do for My Underweight Child?


Most parents want to do the best thing for their child. You may be frustrated and wonder, “Why won’t my child just eat?” It’s easy for parents to feel both frustration and guilt about their underweight child. Before we get into the weeds on helpful things you can do for your child, hear us: your child being underweight is NOT your fault! You cannot force an infant, toddler, or child to just eat or drink more.




However, you can set in place healthy boundaries and structure around eating and mealtimes. You can increase the nutrition in the food that you serve. Doing these things will help set up your child for long-term health success and allow you to take positive steps forward.


We often work with families who have children that need to gain weight and eat more variety of foods. Learn more about how we can help your family. Here are great first steps to take to help your underweight child:

  • Decrease pressure at mealtimes. The less pressure your child feels they are under to eat, the more likely they are to eat more food and try new things.

  • Set up a feeding schedule. Allowing a child to eat all day or whenever they express hunger can really undermine their hunger and cause them to eat less throughout the day.

  • Add healthy fats to your child’s diet. Increase the calorie density of what they eat and drink! This can be done by adding healthy fats to their diet (fats are more calorie dense) in the forms of butters, oils, and other natural unsaturated fats (nuts, avocados, etc.).

  • Use whole fat dairy products. Around two years old, it’s recommended to switch from whole milk to reduced or low-fat milk. More and more, research is showing benefits in favor of whole milk. Keeping a child (especially one who is underweight) on whole milk will help to add extra calories to their diet.

  • Increase nutrition of favorite carbohydrate foods. Adding peanut butter to pancakes or waffles or adding high-calorie drink powders to baked goods like muffins is an easy and fun way to give favorite, easy to eat foods a boost of nutrition.

  • Add shakes or smoothies to your meals. When it comes to liquid intake, pediatricians will usually recommend giving children a high-calorie drink 1-2 times a day. This should not be a meal substitute, but rather an additional intake or replacement of another liquid intake (ex: drinking a high calorie shake instead of milk). For making shakes and high calorie carb favorites we love using Healthy Height shake mix. We will talk more about this below.



Three cups filled with various smoothies and straws on kitchen counter

Is a Supplemental Shake Necessary for My Child?


There are several reasons that may lead your family to pursue a supplemental drink for your child. All of these reasons or situations are individualized. You will need to be in communication with your child’s pediatrician and health care team. Ideally the dietary behaviors, family routines, mindset on eating and food, and feeding habits are all being addressed for the best success for your child and family. Feeding, behavioral, occupational, and/or physical therapies may need to be a part of the health care plan as well. When all these other resources are utilized then adding in a supplemental shake can have the most success and best outcome. Here are some situations where a supplemental drink could be necessary:

  • Your child is underweight (BMI below the 5th percentile).

  • Your child has been diagnosed with failure to thrive.

  • Your child has lost weight.

  • Your child is a picky eater and the number of foods that they are eating is decreasing.

  • Certain medical conditions that may require additional caloric intake, like Cystic Fibrosis.

  • Your child has a high activity level and is not eating enough calories from food alone.

  • Your child has a developmental disorder that is limiting their eating ability (perhaps sensory or texture issues).

  • Your child has ADHD and is struggling to maintain their proper BMI.

  • Your child has a low appetite.


Child drinking purple smoothie with straw


Which Shake or Supplement Is Best for My Child?


There are several options on the market for different types of shakes or drinks for children. Here are how the top few compare nutritionally:


From the chart above, you can see some of the differences in these various kids’ supplemental shake options. We prefer Healthy Height because it offers way less added sugar without losing any of the nutrients we want. The organic Pediasure (which is marketed as “healthier” because of its organic label) offers 17g of added sugar while the Boost vanilla drink has 20g of added sugar. That’s almost an ENTIRE DAY worth of added sugar for a young child.


Healthy Height shake mix also includes 12 grams of protein per serving (without adding the protein from milk) and far less sugar than the competitors (like we can see above), as well as numerous micronutrients like calcium, zinc, iron, and Vitamin A/C/D, to ensure proper nutrition for your child to grow well. And if you are trying to promote weight gain in your child, you can feel good that each serving, when mixed with 1% milk, is 230 healthy calories to ensure improved growth! Check out the full nutritional profile here.



Three cups of chocolate smoothie next to plate of fruit and vegetables and a bag of Healthy Height powder mix

Why We Like Healthy Height for Children’s Nutritional Needs


Not only does Healthy Height contain a better nutrient profile, its ingredient list is one that we can feel confident in. Their powder mix is soy and gluten free, and there are no artificial colors or flavors, no corn syrup, no human growth hormones, and no GMOs included in the mix. Along with having minimal ingredients, it also comes in a variety of flavors- plain, vanilla, and chocolate, so your child is bound to find a flavor they enjoy!


Healthy Height has been shown to help with weight gain, but it has also been clinically proven to improve linear (height) growth and improved sleep patterns. You can read the entire clinical study here. In a study of 200 healthy, lean, short, prepubertal children ages 3-9 years old, those that consumed at least half of the recommended amount of Healthy Height for 6 months demonstrated significant increases in height and weight, compared to children consuming the placebo control supplement. There were notable correlations between the amount of Healthy Height consumed per body weight and gains in weight and height.



Child sitting at counter with Healthy Height mix and unblended shake in front of her

How to Use Healthy Height


We like to make homemade shakes utilizing Healthy Height mixed with milk, bananas, peanut butter, and spinach. Our kids love the way these shakes taste, and they are often asking for more! When a supplemental drink like this is offered in conjunction with a well-balanced diet your child can thrive.


Shop Healthy Height’s products here and use coupon code HH15 for a discount at checkout.



Tell us what your favorite shake to make for your child is below!!



We recently released a podcast episode talking all about this same topic. If you want to listen, search The Doctor and The Dietitian Podcast on Apple, Google, or Spotify or listen straight from our website.


© 2021 The Doctor and The Dietitian. All Rights Reserved.

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