Learn how to help the skinny child gain weight with my feeding and food strategies.

If you have a skinny kid, you may be uncertain about your child’s health.

In this article, you’ll learn what you can do to calm your fears and help your underweight child, including checking their growth chart, offering foods for weight gain (if needed), and more.

Many parents worry about their child’s body size. They wonder about calorie intake. They fear their skinny child is under-eating or under-fed.

I can empathize. I was a skinny kid when I was young. One of my memories is of my freshman year in high school during gym class when all the girls had to get weighed and measured. Even back in the ’70s we were weighed in front of everyone at school. 

Weighing in at roughly 90 pounds, I mostly remember the teacher announcing, “Jill weighs 90 pounds ….” I was the lightest of all the girls in my class. It was one of the first times I felt different. The first time I felt public shame.

I was embarrassed to be thinner, smaller, and behind my peers in pubertal maturation. At the time, I hadn’t “developed” yet. I hadn’t started my menses and I was thin. It wasn’t until I showed up for my senior year in high school that I reached my current 5’8″ and had filled out my frame.

Read: Body Image: How to Prevent Issues in Kids

Underweight or Just Naturally Smaller?

Back then, my parents weren’t worried about whether I was underweight or about my growth and development. I was active everyday playing basketball. I had a voracious appetite and a love of food and eating.

My parents accepted things as they were, and probably recognized that I was very similar to my mother’s frame and maturation tendencies.

Today though, having a skinny kid may cause you to sprout grey hairs and yell incessant pleas from the table to eat. You may worry more about nutritional status, peak growth, and the status of your child’s health down the road.

But here’s the thing: Some kids are genetically inclined to be slight of build, while others, husky.

In a world where so much attention is given to prevention and treatment of kids who carry high amounts of body fat, I know that raising a smaller, skinny child can be just as concerning.

Especially if he’s not eating enough or is a picky eater. Kids with poor appetites also concern their parents.

Naturally, you probably want to help your child gain weight and grow. But, I caution you: Most small kids are fine, especially if they are eating and getting regular physical activity.

Thin kids who aren't eating can be just as concerning as those kids who are overeating. Here's how you can feed the thin child. #skinnykid #fearlessfeeding #healthyeating Click To Tweet

How to Make a Child Gain Weight Fast

If you do have a child who is underweight and you’re worried about whether she is getting enough nutrition, remember, it’s not about getting your child to eat, but rather, creating opportunities to increase calories.

1. First, Check the Growth Chart  

Children show us they are thriving through their normal growth and development as demonstrated on the Center for Disease Control growth charts.  Your pediatrician plots your child’s weight and length/height routinely at well-visits and check-ups. 

Children who are growing normally will track predictably on their own personal growth curve.  Children who are not gaining weight appropriately may demonstrate a flattening of their growth curve. Or, they may show a decrease from their usual growth channel percentile. 

The growth chart is a good indicator of how your child is growing as an individual.

If your child appears to be maintaining a usual and predictable pattern of growth on their own curve, you can rest assured that your child is at a healthy size for them, and getting enough calories.

Read Children’s Growth 101 to learn more.

2. Consider an Age-Appropriate Multivitamin

While children may be naturally or constitutionally thin, some are skinny due to selective or extremely picky eating. These kids may not be getting adequate amounts of vitamins and minerals.

If your child’s diet leaves out one of the major food groups (dairy, fruit, vegetable, grains, proteins), consumes more fast food or processed foods instead of whole, natural foods, or is losing weight or having difficulty gaining weight, a multivitamin supplement may be a prudent addition to their daily diet.

3. Use Weight Gain Foods

Every bite of food and every gulp of liquid can help your child gain weight, grow and be better nourished.

Keep these nutrition “boosts” in mind:  

1. Be sure to add and/or cook vegetables with healthy fats, such as vegetable oil. 
2. Add sauces such as cheese, hollandaise, nut butters, or sour cream to boost calories.
3. Dip fresh fruit in yogurt, fruit dips, or peanut butter. 
4. Double dress pasta–rinse and toss with olive oil, then add butter, cheese or sauce.
5. Choose 2% or whole milk, instead of skim or 1% fat.  
6. Reconstitute soups and prepare oatmeal with milk instead of water. 
7. Boost baked goods such as muffins, cookies, or pancakes with an extra egg or dry milk powder.
8. Serve beverages with calories, such as fruit juice, whole milk, or protein shakes to boost overall calories.  

4. Add a Pre-Bedtime Snack 

Smoothies, milkshakes, instant breakfast drinks or peanut butter toast are good snacks that pack extra protein and calories before sleeping. The timeframe before bed is a golden hour for packing in some extra calories. And they won’t be burned off so readily!

• For some additional snack ideas, check out my 51 Snacks for Kids.

• If you’re stuck in the cycle of junky snacks, read my book, The Smart Mom’s Guide to Healthy Snacking, or take a look at my Healthy Snack Planner. They will help you revamp the way you think about and offer snacks to your child.

5. Stick to a Meal and Snack Schedule  

Plan meals and snacks to occur on a consistent basis, as it can help support the cycle of hunger and promote adequate nutrient intake. Aim to offer meals and snacks every 3-4 hours and maintain this regular routine. And of course, offer balanced meals.

6. Stay Active  

Encourage your child to stay physically active. While this may seem counter-intuitive, it helps build appetite.

Daily activity is part of a healthy lifestyle. Exercise helps build and sustain the appetite cycle, causing hunger, which leads to eating.

7. Don’t Plead, Beg, or Threaten Your Child to Eat 

When you plead for your child to eat more, beg or bribe him with dessert, or threaten to take food away if they don’t eat enough, this sets up a negative dynamic around food for your child. These are also called controlling feeding behaviors, and may backfire in the long run, causing your child to be pickier and/or eat less. 

What should you do instead? Provide several opportunities to eat using a regular schedule of meals and snacks. And, offer nutritious, acceptable foods. Although you can’t force your child to eat, you can allow him to choose which foods he’ll eat from what you have offered and let him make decisions about how much he will eat.

What about Weight Gain Supplements (like Pediasure)?

I’ve had a number of parents ask about weight gain supplements such as protein powders and shakes.

While there are some products on the market that tout the ability to help children grow, like Pediasure, the reality is a child needs to like these products and be willing to drink them. Many of the commercial products are formulated with children’s needs in mind. They can add a calorie and nutritional boost to a child’s overall diet.

Homemade weight gainer shakes, or a boosted milk drink, like Carnation Instant Breakfast or Ovaltine (both of which get added to milk) can do the trick, too. I like to use whole milk, whole milk yogurt, peanut butter, honey, frozen fruit like mango, and flax oil to concoct a high calorie high protein beverage.

Offering something like this at night, before bedtime, can help. The most important things to consider when thinking about weight gain supplements are:

• Your child enjoys drinking it
• It is appropriately made for the pediatric population (the amounts of nutrients aren’t too high for kids)
• Your child doesn’t become reliant on them
• They’re working well, and not crowding out the ability to eat other nutrient-rich foods

Warning: Many weight gainer supplements are designed with adults in mind and may be too high in vitamins and protein for a young child. And remember, supplements are a short-term fix. You don’t want your child on them for the long term.

Thoughts for Skinny Boys

Today, boys may feel an inordinate amount of pressure to be muscular – even before it’s biologically possible for them to bulk up their muscles. The latest science tells us that boys are developing body image problems and eating disorders at an increasing rate.

If you have a skinny boy, be on the lookout for changes in eating, particularly eating more protein to bulk up, and dissatisfaction with body appearance.

Tune in to my podcast interview with author and researcher Charlotte Markey on this topic.

Skinny Girl Alert

Similar to skinny boys, girls can feel just as inadequate when they are smaller bodied or have trouble keeping weight on. Equally as disturbing, though, are those girls who are trying to get skinny through dieting, purging or other means of losing weight.

Be on the lookout for behaviors that predict disordered eating and eating disorders. I’ve got more details in The Eating Disorder Guide.

Need More Help?

Remember, some children have body types that are naturally smaller, lean, and thin. This is part of their constitution, or genetic make-up. Some kids may be thin due to suboptimal or inadequate nutrition.

You’ll see a downturn on their growth chart and they may classify with an underweight BMI.

If you’ve tried these suggestions, consider further assistance from a Registered Dietitian or your pediatrician if you are concerned about your child’s weight.

If you think part of the problem is related to a limited food variety, my book, Try New Food: How to Help Picky Eaters Taste, Eat & Like New Food, can help!

It takes you through some steps to encourage your child to expand his food repertoire without pressure or negative feeding.

Want more expert tips? Check out my podcast, The Nourished Child!

CHILD UNDERWEIGHT? | EVERYTHING YOU NEED TO KNOW so Your KID CAN GROW (from a Pediatric Dietitian)

This post was updated in June, 2020.