Skinny Baby – Should You Be Worried?

Mumeemagic is reader-supported. When you buy through links on our site, we may earn an affiliate commission.

Skinny Baby – Should You Be Worried?


Chubby cheeks, roly-poly belly, and soft mushy thighs – isn’t that where your imagination takes you when you hear the word “baby?” Baby fat does not concern people as they regard it to be a sign of a healthy baby. On the contrary, if a baby looks skinny, people conclude that the baby lacks nutrition and has some weight-related issues.

The question is – is a skinny baby an unhealthy baby, and should you be worried about your little one? There can be a myriad of reasons behind a baby being underweight. You might consider taking your little one to a pediatrician if you think they are skinny or their weight is not increasing.

The first factor you should analyze is if your baby is genetically lean or underfed. A feeding plan and a few couples of extra measures would bring your baby to an average weight. Let’s dig deeper to understand if you should be worried if you have a skinny baby and if you should talk to a doctor about it.


How to Know If Your Little One is Underweight?

Before you move on to understanding the reason behind your baby’s low weight, let’s help you know which babies qualify as underweight. Pediatricians can tell you this by referring to growth charts by the World Health Organization (WHO). This chart applies to all newborn babies and kids up to 2 years.

WHO’s growth charts are based on years of concrete research. It is also worth mentioning that the charts for baby girls and baby boys are different. You can also determine whether your child is underweight by other factors – their eating habits, medical problems, body & weight structure, and how long they have been skinny or malnourished.

A doctor might also suggest you refer to the Body Mass Index (BMI) of your little one. If your child’s BMI is below the 5th percentile, they are considered an underweight baby.


5 Reasons Why Your Baby is Too Skinny

A poor feeding schedule or slim pickings is not always the reason behind your baby’s skinny appearance. If you dig deeper, there’s much more that is contributing to your baby’s low weight. This section of the article will try to decode all the reasons behind a skinny baby. Keep reading!

Reason 1 – Genetics

Genetics can be the top reason behind your baby being skinny, and that’s a no-brainer. Sometimes, in an attempt to put your baby at the right point of the growth chart, you forget to consider genetics. Genetics plays a critical role in determining your baby’s overall size.

You must think – How tall am I or the other parent is? Were you and your baby’s other parents skinny in their childhood too?  If you and your child’s other parent have a lean appearance, it is pretty natural for your newborn baby to share the same traits.

But, it is worth noting that the genes for size might not be active up until the point of infancy. Your baby’s overall weight and height depend more on birth weight in an initial couple of years.     

Reason 2 – Low Birth Weight

Did you have a premature delivery? Or, was your baby underweight during birth? If it is either of the two, your newborn might continue to be skinny for the first few months or, maybe even longer. Besides, a baby with a regular, high, or low weight will fluctuate during their development stages.

A marginal slip in height and weight in the growth curve of the baby is nothing problematic. However, if the fluctuations in weight are too frequent, you should talk to a doctor. Sometimes, the frequent changes in the growth curve can indicate an underlying health problem.

Reason 3 – Digestive Issues

You might be surprised to hear that another reason behind your baby’s undernourishment could be digestive problems. An infant can suffer from digestion-related problems. For example, gastroesophageal reflux disease and inflammatory bowel disease can cause the baby to be underweight.

If your baby is refusing to consume anything, it might be because of heartburn or bowel pain. If there are symptoms like diarrhea or vomiting, we suggest you seek immediate healthcare for your baby.

Reason 4 – Thyroid-Related Problems

Thyroid problems can be another leading problem that causes a baby to be skinny. Many babies have an overactive thyroid. Such babies might suffer from hyperthyroidism. Hyperthyroidism is one condition that causes them to lose weight.

Also, if your baby is always irritated or nervous, it could indicate the presence of hyperthyroidism. The baby will need a detailed blood test to confirm the diagnosis.

Reason 5 – Eating  Disorders and Slim Pickings

It is no secret that babies do not share a friendly relationship with healthy food. They are notorious for being picky with food. With these slim pickings, the kids are at risk of developing a deficiency of minerals and vitamins. These kinds of eating habits can cause them to be underweight.

Also, in recent times, eating disorders have become a common problem with a child’s weight. If your child has eating disorders, they might vomit after consuming their meals. It might also cause them to reduce food consumption to an unhealthy level. Naturally, such babies tend to be skinny.


Can a Skinny Baby be Healthy?

No matter how much your neighbors or relatives insist on it, skinny babies are not always sick babies. When your munchkin does not have rolls, everyone around seems to think something’s wrong.  If your child is meeting all the developmental milestones, there’s nothing to worry about.

You can ask your pediatrician for all the age-based milestones. Some of the milestones are holding up their head, rolling over, smiling, and crawling. These small actions are signs that your baby is progressing as it should. Sometimes parents get better results from changing the baby’s diet.

Consistent poopy diapers, happy mood, playful temperament, and regular wet and dirty diapers are a few other signs of a baby that’s doing perfectly well. 

What is a genetically lean baby?

Genetically lean babies are ones whose genes predispose them to be leaner than average. This can be due to a variety of factors, including having parents or grandparents who were lean or having a naturally high metabolism. While there is no guarantee that a genetically lean baby will remain thin into adulthood, it is more likely than not that they will.

Growth Opportunities for Your Skinny Baby

We get it; feeding a baby is not easy. Parents have to find all sorts of creative ways to get a spoon of food into their munchkin’s mouth. Luckily, we have some simple tricks up our sleeve that parents can use to keep their little nuggets at a healthy weight. Below, we’ve enlisted different ways through which you can manage your baby’s weight:


Limit Intake of Junk Food

Are you feeding too much-packed food to your little one? Often, parents resort to packed and canned meals that advertise themselves as healthy and apt for kids. However, it is not the truth. As a parent, you should cut back on this kind of ‘junk’ food for babies. Continuous intake of junk food will also create an aversion to food that is healthy for them. 

These packed foods are not exactly rich in vitamins and minerals. Soo, your baby is filling his tiny belly with foods that have no nutritional value. It is also a wise move not to introduce your baby to junk food at a young age. Try to replace the intake of junk food with other healthy snacks and meals.

High-Calorie, Nutrient-Dense Meals

Try to add healthy sources of fats and vitamins to your baby’s meal. Avocado and olive oil have both health benefits and calories. The oleic acid in these foods reduces inflammation, and they are rich in omega3 fats. You can also opt for fruits with high-calorie content. But, these foods are only safe once your baby has passed the 6-month milestone. 

We also suggest fruits like bananas, oranges, apples, and pears for the best development. These foods are really good for your baby’s overall development!

Stick to a Strict Eating Schedule

Are you feeding your baby at random times? Many parents respond to their baby’s cry with food. Feeding in untimely and at different intervals fills your baby’s tummy. So, your baby might throw tantrums while you try to feed them their main meal. 

Besides, adhering to a strict schedule will help your baby acclimatize to proper eating frequencies.



Get your little one moving! It is okay to start exercise for babies early (Not of course, on the treadmill!). Encourage your baby to hit the ground and make some movement. You can try creating safe play areas where they can crawl and roll.

The idea here is to keep them active. A good level of activity will also make the babies hungry. When they are ready to walk, you can take them out to the garden or lawn for some playtime. Physical activities will increase their requirement for vitamins and other sources of energy.

Feed Dairy Products

Once your baby is out of the “breast-feed and bottle-feed” phase, you can go the extra mile and make their meals apt to bulk them up! You can take the help of dairy products to encourage weight gain in a skinny baby. You can add grated cheese to soups and meals.

Additionally, you can also feed them full-fat yogurts. But don’t pick the yogurts that are laden with sugar.

Make Meals More Entertaining

Is your little one not interested in consuming anything? Perhaps you can try a different way to evoke their interest in healthy meals. The first thing you can do is try dining together. When your baby sees other family members eating, they might readily consume food. 

Also, make their meals more interesting. Try introducing new toys and other sources of entertainment to distract them. Also, if your baby likes a specific healthy food, it is better to feed them in good frequencies along with other dishes.

Cut Down on beverages

Liquids are essential for hydration. However, filling your little one’s appetite with beverages is not ideal. Limit juices and milk as they might ruin the baby’s appetite. Instead, focus on healthy, solid foods, and nutrition-packed foods.

The difference between formula-fed babies and breastfed babies

Formula-fed and breastfed babies differ in many ways. One of the most obvious differences is in the way they are fed. Formula-fed babies are fed with formula, while breastfed babies are fed with breast milk.

Another difference between formula-fed babies and breastfed babies is in their immune systems. Breastfed babies have been shown to have stronger immune systems than formula-fed babies. This is because breast milk contains antibodies that help protect babies from infection.




How to Understand If My Baby is Underfed?

You can spot an underfed baby by analyzing their behavior. If the baby is underfed, it will not engage in activity or act playful. The baby will act snappy and be fussy about everything. If you notice this kind of behavior in your child often, it is a sign of underfeeding.

That also brings us to the fact that a crying baby is not a sign of an underfed baby. Babies can have a myriad of reasons for crying or being fussy. Lack of sleep, temperature, and bellyache are a few other reasons why your baby might be crying. Your responsibility as a parent is to test and understand the baby’s behavior and find what it needs.

What is Failure to Thrive in a Baby?

Failure to thrive in babies is a condition where they are not growing as they should. Doctors can diagnose a case of failure to thrive when the baby’s rate of weight gain is much below that of the average weight.

It is a condition that is related to the physical development of your child. The good news is that failure to thrive is reversible. But, the treatment depends on the symptoms and also the age of the baby.

Is it Bad if My Baby is Skinny?

If your baby exhibits normal activities and behavior, you have nothing to worry about. The steady growth of their child should be the focus of every parent. If you are still worried about your baby being skinny, you can consult a pediatrician.

For most of the time, a skinny baby is as healthy as a chunky baby. So, you can keep your worries aside and focus on your child’s feeding plans and keeping them active!

Which Vitamins Are Best for Baby’s Weight Gain?

Making your baby gain weight can be an arduous task. But, you can ensure weight gain by filling them up with the right vitamins and minerals. Vitamins and minerals can support healthy weight gain and enhance metabolism. Here’s a list of vitamins that work great for a baby’s weight gain:

  • B vitamins
  • Vitamin D
  • Calcium
  • Iron
  • Magnesium


What Foods Are Great For Increasing My Baby’s Weight?

As parents, you might be frantically looking for ways to fatten up your underweight munchkin. Though most skinny babies tend to gain weight as they develop, some might need a little extra push. You might also be willing to try different ways yourself before taking your little one to a doctor.

Here are some foods you can try feeding your baby to encourage weight gain in them:

Olive oil or clarified butter

  •         Nut butter
  •         Milk
  •         Avocado
  •         Bananas
  •         Hummus
  •         Cheese
  •         Oatmeal
  •         Pear
  •         Yogurt
  •         Pear

Additionally, it is ideal to breastfeed your baby for as long as possible. You can also ask your pediatrician for a meal plan to help your baby with its nutritional needs.


If My Baby is Skinny, Should I Take Them to a Pediatrician?

If you are worried about your infant’s weight, it is a good idea to consult a doctor. Their expert suggestions will give you peace of mind over your baby’s health. A healthcare professional is the right person to tell how you should proceed with the scenario.

They can also offer consistent advice on how to bulk up your little one in a safe way. Plus, most pediatricians also offer meal plans to help you.


Key Takeaways

If your baby is not chubby, it is not always unhealthy. The notion that your munchkin needs to have rolls of baby fat to be healthy should be let off. If your baby is touching all the developmental milestones, is active and playful, you should drop your worries.

Your baby’s well-being is all about consistent growth and not exponential growth. When it comes to a healthy baby, you should take your pediatrician’s word for it. If your little one needs to bulk up a bit, don’t worry. There are a variety of ways you could bring your little nugget on to the weight-gaining track!




This post is written and edited by Sandy who is a clinical pharmacist with over 20 years of experience specializing in pre-natal and post-natal care.