How To Get Your Kid Back on Their Growth Chart 

If you're a parent worried about your child being underweight, you're not alone. Experts share what to do.

Close up of a pediatrician using a baby scale to measure the weight of a newborn baby
Photo: Getty Images

Recently, while at a restaurant with my husband and 5-year-old son, I asked the waiter for milk. "I'm sorry, but we're out of low fat. We only have whole milk right now," he said, apologetically.

"Oh, that's wonderful," I beamed. "You have no idea how happy this makes me."

Watching my almost kindergartener, Jack, blow bubbles in—then finish—his tall glass of full-fat milk, along with his plate of broccoli mac and cheese, was more fulfilling than an hour of therapy.

I wasn't always a person who clapped my hands in elation when offered whole milk at a restaurant. But then my son was born in heart failure—doctors had detected two holes in his infant heart and a malformed mitral valve at my 20-week ultrasound. I watched beads of sweat form on his little head as he attempted to breastfeed in the post-natal hospital room. "When he drinks, it takes up a lot of energy, almost like he's running a marathon," said the nurse. It didn't help that he also had a severe case of reflux, which caused him to throw up almost all the milk we could get him to drink.

The more he grows, the bigger his heart will be, and the easier it will be for the surgeons to fix it when surgery is needed. That was the mantra we repeated silently as I breastfed and pumped, as we stirred special formula into the milk to increase the calories, as one of us fed Jack the fortified bottle while the other padded to the kitchen to wash the pump flanges and measuring cup to start the circuit all over again. It's the same mantra we repeated each time Jack projectile vomited onto the wood floors. And we kept repeating it when a nurse inserted a feeding tube down one of his nostrils at the hospital, when he had his first open-heart surgery at 4 months old, and then as I gave him his first solid foods and met with dietitians, nutritionists, and feeding specialists every week until his second surgery at 2-and-a-half years old.

By then, his weight chart looked like a toddler's dot marker painting—a blob of black points above and below the third percentile that made the pediatrician's forehead wrinkle. She understood that we were doing everything we could, given the circumstances, but explained that lack of growth over time could mean that Jack wasn't getting enough calories to foster healthy brain and body development.

Finally, after Jack recovered from his second open-heart surgery, the reflux disappeared and he began to put on weight, rising slowly to the fifth percentile by the time he was 3, then higher. Now, at 5-and-a-half, he's cruising steadily along the 10th percentile curve. The tension that hung over our dining room table has lifted, and our new job is to help Jack develop a healthy (less pressured) relationship with food, a challenge of its own.

Learning I'm Not Alone

After posting a survey for parents with underweight toddlers and school-age kids on my local parents Facebook group, I quickly learned I'm not alone. Ten people responded in just three days. A few explained that their underweight kids are just picky eaters. Some parents listed chronic health conditions as the culprits for their children's lack of weight gain, including congenital heart disease, growth hormone deficiency, epilepsy, and reactive airway disease. A few mentioned that medications their kids were prescribed caused a general lack of appetite. Others responded that their kids had trouble gaining weight in infancy because of reflux, food allergies, or lip and tongue ties, then developed selective eating habits as they got older. "Weight concerns led to unconscious force-feeding, which led to picky eating and further food refusal," wrote one mom.

Though the reasons varied widely, I could hear the same exhausted sigh in each response. The same frustration that this impossible balance created. "Make sure your child puts on weight, but don't show them you're stressed about mealtimes, and always feed them healthy foods!"

Beth Leonberg, DHSc, RDN, director of dietetics education programs at Drexel University, agrees these messages can be difficult to sort through, especially when there's much more emphasis on the other end of the scale. "We have these overwhelming public health issues, like obesity and heart disease and type 2 diabetes, and that's what drives all the public health messaging and guidelines," she says. "When you're on the opposite end, it's hard."

How To Help Your Child Gain Weight

About 4.1% of kids and adolescents are underweight, according to the Centers for Disease Control and Prevention (CDC). If you're one of the many parents struggling to help your kiddo gain weight, not lose it, here are some real-life strategies and mindset shifts that might help.

Use your team

Maybe your child is a picky eater, and some simple tweaks at home might be all you need to get them back on track. On the other hand, if weight gain continues to be an issue despite all your best efforts, ask your pediatrician to connect you with a gastrointestinal specialist, allergist, dietitian, nutritionist, occupational therapist, or other specialist who might be able to help.

"Don't stop looking for a root cause," says clinical nutritionist Stefanie Haris, DCN, whose own daughter was diagnosed with growth hormone deficiency at 4 years old. "Sometimes a child isn't feeling great because they're allergic or have a sensitivity or some other issue that needs to be supported," she explains. "But once their belly feels better [due to interventions like medication or diet changes], they might be able to eat more and put on more weight."

Create a mealtime routine

Try and serve breakfast, lunch, dinner, and snacks at the same (or close to the same) times each day, and encourage your child to stay at the table for a certain amount of time at each meal. Dr. Leonberg suggests starting small, then working up to a 15- to 20-minute stretch at the table for toddlers and preschoolers, and 30 minutes or longer (depending on how long the family stays at the table) for older kids.

When your child gets up from the table, explain that they won't be eating again until the next meal or snack time. "If [kids] eat little bits of food continuously throughout the day, they keep hunger at bay but never eat sufficient quantities to meet their needs," says Dr. Leonberg. The point of a mealtime routine is to not only offer structure, which is comforting to children, but also allow your child to feel hunger so they will eat more at each sitting.

Make every bite (and sip) count

When she's working with kids who need to gain weight, Dr. Leonberg teaches parents to increase the nutrient and calorie density of each meal, rather than offer their children extra food. "We don't want to add multiple extra servings of things or require them to drink twice as much of something," she says. "Instead, what we want to do is pack as many calories as possible into what they would normally be eating."

Some of her go-to tips include buying all whole-fat dairy items, like milk, yogurt, and cheese; building meals around naturally high-fat foods like avocado, egg, salmon, and nuts; adding a teaspoon of melted butter or any type of oil to breakfast, lunch, and dinner servings; and accompanying "plain" snacks like raw veggies and pretzels with little bowls of ranch dressing, peanut butter, or cream cheese.

Also, don't forget about beverages. "Kids need adequate fluids," adds Dr. Leonberg, "but it doesn't have to be water. Every beverage should have some calories in it, like milk or no-sugar-added fruit juice."

Offer weight-gain shakes only as directed

Nutritional shakes are great for giving your kid a boost of extra calories between meals, but they shouldn't become the bulk of their diet. Speak to your child's pediatrician or nutritionist first and see if they recommend one. Though these drinks are clinically shown to help kids gain weight fast, relying on them too much can result in unhealthy eating habits. "Weight-gain shakes should be used with the guidance of a nutritionist or therapist, so they don't become a crutch," says Lauren Rice, a pediatric occupational therapist, noting that a diet consisting of only shakes and soft foods can also cause kids to skip over developmental milestones related to oral motor skills and even speech.

Encourage food engagement

The more your child engages with their food, the more likely they are to eat it. Let your child explore their meals with all five senses. What does each food look like? What does it smell like, both before and after cooking? How does it feel in your hands, in your mouth, and as you swallow? What does the food taste like? And what does the food sound like when you snap it in half or chew on it?

Rice also encourages her clients to involve kids in food shopping, meal planning, and cooking, if possible, "whether it's just watching [you] prep the food, putting seasoning on their own serving, or talking about what the food looks like before it's cooked, then after."

Let your child control what they eat

"Parents who pressure kids to eat more will end up with the opposite result," explains Dr. Leonberg. "Pressuring leads to kids being restrictive in their intake and actually can contribute to the development of eating disorders."

Space out their meals throughout the day so your child can recognize their own hunger cues; practice sitting at the table for a certain period of time; expose them to a variety of tastes, textures, and cuisines; and resist the urge to bargain with them to eat more or demand they clear their plate. When they feel empowered and in charge of their own body, they are free to make healthy food choices for themselves. And those choices will form the foundation of your child's eating habits when you aren't there to monitor them (at daycare, grade school, camp, college, etc.).

Manage your own anxiety

It's natural to feel stressed when your child is underweight. However, if you don't take steps to manage your anxiety, you might end up creating a negative mealtime environment that makes the problem even worse. Include other family members in mealtime planning and prep if you can, practice deep breathing, or reach out to a therapist, and remember that this is just one part of caring for your child.

"It's definitely challenging to take my own advice sometimes," says Dr. Haris, referring to her own daughter's weight gain issues, "but then I think about how, in real life, many of the kids I knew who were selective eaters for various reasons are fully functioning adults now, and I take a breath and go, 'It's going to be OK.'"

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