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Is your child underweight? Here are some tips from a registered dietitian nutritionist on how to feed your child to ensure that they get the nutrition and support that they need to grow and thrive, REGARDLESS of their weight. 

It’s natural for us, parents, to worry. And when it comes to our child’s appearance, if they look thinner (or heavier) than how we or society “thinks” they should look, we take action!

But before you take drastic measures, I hope reading this post will help you to reframe your mindset of “I need to increase or cut back on calories to have my child be a certain size” to one that values nourishing your child both inside and out.

2 bear wooden plates laid side by side with left one showing what you think your child needs vs. what your child needs on the right
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From birth to age 2, pediatricians and dietitians monitor growth on a weight-to-length measurement using charts from The World Health Organization (WHO). It’s based on gender and lots of data. During this time, their head circumference is also measured to make sure that the brain is growing properly. 

After 2, growth charts from the Centers for Disease Control (CDC) are used to look at weight, height, and body mass index (BMI) for age.

These charts allow for comparison of your child’s growth to that of other same gender and age children.

So if a child is in the 5th percentile for weight, that means they weigh less than 95% of other children that age. A child in the 90th percentile weighs more than 90% of other same-aged children. 

What’s considered normal growth?

There are so many factors that influence how your child grows, such as genetics (that’s a HUGE one), nutrition, environment, and activity. Remind your self of this next time you find yourself comparing your child with how your family member or friend’s child is growing.

The most important thing to recognize is that every child is unique! If your child is in the 10th percentile, this doesn’t mean they’re doing better or worse than your friend’s child who is in the 70th percentile. 

Instead of focusing on the number, what’s most important is whether or not your child is tracking predictably on their own personal growth curve. In other words, are they staying on relatively the same percentile line?

You can rest assured that your child is getting adequate nutrition and growing properly if they’re maintaining a usual and predictable pattern of growth on the curve.

If you start to see big jumps, dips, or flattening of the growth curve, those are red flags.

What’s considered underweight or overweight

Here are the official qualifications:

  • Underweight: a child is in the bottom 5th percentile on the BMI growth chart
  • Overweight: a child is at the 85th-94th percentile on the BMI growth chart
  • Obese: a child is at the 95th percentile or higher on the BMI growth chart

BMI doesn’t tell the whole story

While BMI can be a useful place to start, it is NOT a good indicator of health nor predictor of disease risk. It’s a quick and easy screening tool because it relies SOLELY on height and weight.

Now you can see why this is so flawed. It doesn’t take into consideration many factors that can influence BMI and body fat, such as age, gender, ethnicity, muscle mass, fat distribution, etc.

A higher BMI doesn’t necessarily mean excess weight. Let’s use an example. A child with a high BMI may have a large frame, a lot of muscle, and no excess fat while a child with a normal BMI can have a small frame with excess fat.

Again, BMI is NOT a reflection of health. An individual can be healthy with a low or high BMI while an individual with a normal BMI may be unhealthy.  

Therefore, take your child’s (and your) BMI with a grain of salt. Instead, as I just emphasized, refer to your child’s growth chart and look at the trends over time. And I always like to remind parents that there is no ideal weight for our children as they are always growing!

Health is attainable at every size! 

Tips on how to feed regardless of weight

As you know, early childhood is such a critical time for establishing healthy eating habits. Research shows that eating behaviors and meal habits in early childhood have a tremendous impact on food preferences and eating patterns throughout childhood, adolescence, and into adulthood. 

While it’s tempting to take drastic measures to feed your underweight or overweight child, I can’t emphasize enough that best feeding practices remain the same regardless of your child’s size. 

Your small or large child is just as trustworthy about regulating their food intake as is the child who is average-sized.

My #1 tip: Focus on healthy living and healthy habits over weight! 

followed very closely by my next one

My #2 tip – Stick to the division of responsibility.

We, as parents, are in charge of feeding, while our kids are in charge of eating. By following the division of responsibility, your child’s innate ability to self-regulate will help them to grow into the body that is right for them. 

Here are some additional tips:

  • Offer a variety of nutritious foods. It’s important to constantly expose your child to a wide variety of foods with different flavors and textures.
    • Make sure there’s always something on the plate that your child loves and feels safe around. 
    • Start by offering a small portion. Especially if your child is underweight, it’s easy to overfill their plate. But large portions can be overwhelming and shut off their desire to eat. On the other hand, larger portions may encourage overeating in some children. So start small and offer more if your child asks. Always follow their lead. Trust their appetites.
  • Limit (not eliminate) palatable, energy-dense foods
    • If you have an underweight child, you might be tempted to offer high-calorie foods, like ice cream, juice, pizza, milkshakes, etc. And while it might add a few pounds to your child, those foods will not provide the nutrients they need to grow and thrive.
    • On the other hand, if you have an overweight child, you might be desperately trying to eliminate these foods from your child’s diet. But restriction is totally ineffective and only backfires. In fact, research shows that parental restriction promotes overeating and is linked to higher weights and poor eating habits. 
    • So now the question is – how do you handle these energy-dense, low-nutrient foods? You shouldn’t restrict but a free-for-all approach is not good either. Answer: Structure without restriction!
  • Take control of the pantry. If you find that you’re unable to maintain the “kitchen is closed” policy because your child is constantly rummaging through the pantry, then rethink what you’re bringing home from the store. What they have access to is what they’ll get used to and learn to prefer in the long-run.
  • Set and stick to a snack and meal schedule
    • If your child is underweight, you might be making food available around the clock in hopes of getting your child to eat more. If your child is overweight, you might be tempted to take away a snack or two.
    • Don’t do it! They will have the opposite effect and will lead to either sabotaging their appetite or overeating.
    • Instead, children thrive on routine and structure so let’s give it to them! This will be so instrumental in promoting appetite regulation and healthy habits. Your child will learn that eating happens every 2-3 hours (older children can go longer) and that the kitchen is closed outside of those times.
  • Let your child do their job of eating. This means, once you put food on the table, your job is done. Do not interfere by getting them to eat more or less. Negative feeding practices, such as rewarding, bribing, punishing, will not only undermine the healthy eating habits that you’re trying to teach your children, it will interfere with their natural ability to self-regulate.
  • NEVER put them on diets. Research shows that dieting is a risk factor for both obesity and eating disorders. In fact, dieting behaviors were associated with a twofold increased risk of becoming overweight and a 1.5-fold increased risk of binge eating.
  • Serve ONE meal for the whole family! You don’t want to single out your child by offering different food. 
  • Lead by example. It’s true. Those precious eyes are always watching! So eat the way you want your child to eat. And if you’re struggling with an unhealthy relationship with food, it’s time to get help. Otherwise, it may unintentionally get passed down to your child.
  • Make eating together as a family a top priority. It’s a wonderful time to connect and build trust with your child around food.
  • Maintain a positive, safe eating environment.
    • We want our children to associate food and eating as a source of joy and nourishment rather than as something to despise or be scared of. So make the table a place that exudes positivity.
    • Don’t watch your child like a hawk as they eat. Take the focus away from the food and instead make mealtimes about spending time together⁠ The more they find enjoyment, the more they will be motivated to make healthy choices.
  • Cut out the weight talk.
    • This could be comments made by family members about their own weight or comments made to the child.
    • It’s a known risk factor for obesity and eating disorders.
    • Don’t bring weight into healthy eating conversations. Otherwise, it will send the wrong message to your child that healthy eating is all about weight control.
    • However, research shows that if the focus of the conversation is ONLY on healthful eating behaviors, overweight children are less likely to engage in unhealthy weight-control behaviors.
2 bear wooden plates laid side by side with left one showing what you think your child needs vs. what your child needs on the right

Tips for feeding an underweight child

Feeding our little humans is challenging in many ways as we, as parents, put so much pressure on ourselves to make sure that they grow grow grow! And when your child is underweight, it’s so difficult not to get consumed by wanting to see your child put on those extra pounds.

While you may be feeling like you failed as a mom, I’m here to remind you to shower yourself with grace! The fact that you care so deeply just shows what a wonderful mom you are!

Body size is NOT an indicator of health! Your child can be small and healthy!

As tempting as it may be to follow your child around and force your child to take another bite, stick to the division of responsibility and focus your efforts on implementing the tips I’ve shared above.

Additional tips:

As mentioned earlier, don’t overfill the plate. Start with a small portion and offer more as necessary. If your child has a small appetite, try to make every bite and sip count.

Here are some ways you can do this:

  1. Add extra oil, butter, cheese to meals
  2. Cook veggies in extra oil, butter, tahini, etc. You can also serve them with high-calorie dips like nut butters, yogurt, guacamole, bean dips, etc.
  3. Go for the full-fat. Although the recommendation is to switch to low-fat milk after 2 years of age, I personally am still giving my 2.5 yo whole milk and plan on continuing to do so. You can read more about it in this post – What’s the best milk for toddlers?
  4. Nutritional supplements? Many families turn to these as they are a convenient way to boost calories and nutrients to support weight gain. My personal recommendation is to focus on food first. However, if your child is really struggling, then talk to a dietitian or health care provider to find the type that is most appropriate for your child.

Having said all this, here’s what I REALLY want to emphasize – your small child is entitled to eat as little as they’re hungry for. They are just as trustworthy about regulating their food intake as is the child who is average-sized. Let that soak in a little bit.

Hope this was helpful! On the flip side, if your child is a little bit heavier, here’s what you can do to help them be healthy and happy – How to Help Your Overweight Child.

About Min

Thank you so much for stopping by! I am Min, a Registered Dietitian, a Christ follower, a wife, and a mom to our two miracle babies! Currently, I’m having a ton of fun feeding their tummies and sharing our baby led weaning journey! Follow me on Instagram if interested in seeing daily menu as well as tips and tricks.

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  1. Oh my God..This Has put me on ease..Thank you so much for the Love,Such kind words for parents with Underweight babies

    1. Hi! What we’re looking for is whether or not they are following their growth CURVE. So if it’s flattening then it means they’re not growing. Take a look at your chart and you can see that if it flattens, they’re no longer in the same percentile.