Are Breastfed Babies Smaller? (Breastfed vs. Formula Fed)

Breast milk is constantly changing to meet the baby’s increasing body demand. Breastfed babies have to suck hard to get the letdown, and this is a tiring process for your little one. On the other hand, Formula milk contains many sugars that cause the baby to achieve faster, but it lacks the nutrients contained in breast milk.

I breastfed my baby as a personal choice. My baby was healthy, born 9lbs at the time of birth, gained weight in the first three months, around 12lbs, and maintained a pretty good weight.

However, he didn’t gain much weight when he started walking, maybe because of his increased daily activity. According to my pediatrician, he ranked at the 30th percentile on the baby body weight chart.

Growth charts and breastfed babies

As much as I was curious about my baby’s growth, I think you are too! Well, there are plenty of ways through which we can measure our baby’s development.

Both mom and baby are laying down on the bed, while mom breastfeeds her newborn baby.

The most reliable one is the WHO growth chart. It was published in 2006, keeping in mind the new growth standards of babies exclusively breastfed to nonsmoker mothers.

In comparison, the previous chart was based on the growth of formula-fed babies. 

Growth charts are just ways to determine the average body weight of the baby. It is not a race to achieve the 100th percentile. It is instead a nice and easy way to measure and evaluate their growth.

The baby’s development does not solely depend on the ratio of this growth chart.

Other factors that predispose the cause of growth in babies include genetics, body type, or physique. When visiting your pediatrician, he might also ask few questions and use a growth chart measurement.

  • What are the body type and physique of babies parents?
  • What was the growth pattern of parents?
  • What is the growth pattern of siblings?
  • Is the baby gaining weight consistently despite having low weight?
  • Is the baby achieving all of his developmental milestones?
  • Is the baby alert, happy, and responds quickly, or is he agitated, restless and fussy?

Another way through which you can keep track of your baby’s weight is by using different apps. For example, you can add your baby’s weight in grams and age in the months. It will quickly calculate and show you the result.

Measuring your baby’s weight by using an app is quick and easy for parents these days, which you can do at any time.

Or you can even manually note weight gain changes every week to keep a tab of their growth.

Breastfed vs formula fed babies

Breastfed Formula-fed
Different studies have shown that breastfed babies have a smaller head and lose about 6% to 8% of body weight. But his is completely normal.
Eventually, breastfed babies gain weight in the first three months as a newborn equal to formula-fed babies. The reason being, their demand is similar.
However, over time formula-fed babies tend to gain more weight than breastfed.
Firstly, formula milk contains many sugars, fats, and babies retain water for a long time, explaining weight gain. Secondly, breastfed babies have to suck vigorously to get the letdown (frequency of feeding).
Breast milk constantly changes according to the baby’s body requirements. It improves metabolism and provides nutrients that the baby needs with increasing demand.Formula doesn’t contain as many nutrients as compared to breast milk. However, it remains the same and produces the same results for a baby irrespective of how old they’re.
Studies have shown that breastfed babies had low-calorie intake and volume of milk as compared to formula-fed babies. This certainly doesn’t mean that their mothers aren’t producing much milk according to their needs.Formula-fed babies consume much more calories than breastfed babies because formula contains added sugars and fats.
Breastfed babies have an incredible ability to regulate their calorie intake according to their needs. They determine how much milk they need according to their body’s requirements.Typically, formula-fed babies are overfed. It’s because it’s much easier to feed with a bottle. Also, easier for the baby to consume formula milk. So, it’s up to the parent to control the consumption.

Ways to increase weight in breastfed babies

Mom is trying different methods to help increase the weight of her breastfed baby.

Here are specific ways you can increase the weight of your breastfed baby.

  • Are they latching correctly? At times babies have trouble latching and drink less milk than needed.
  • Try a pacifier. It increases the baby’s sucking time. 
  • Try switching breasts every 5 to 10 minutes. Also, take your feeding position into consideration.
  • Feed your baby on demand. But it’s also easier for both of you if you plan a scheduled feeding sessions throughout the day.
  • Put your baby to sleep next to you and nurse uninterrupted at night. This routine helps reduce stress, agitation and fussiness in breastfed babies. They also feel closer to you.

Average growth patterns of breastfed babies

Mom is breastfeeding her newborn baby while holding her.

Momma, as everyone says, babies come in all shapes and sizes, just like adults. We were all once babies, and our genetics determined our growth pattern. 

Focus on the baby’s growth, not the chart. It is certainly not the perfect evaluation measurement tool. But, as long as your baby is healthy, in the required body mass ratio, and achieving their milestones, you shouldn’t be worried about what anyone else says. 

Here I’ve gathered information about the growth pattern of the average breastfed baby according to CDC guidelines.

  • Weight gain of 5 to 7 ounces (170 grams) per week for the first four months
  • Weight gain of 4 to 6 ounces (113-150 grams) per week for 4 to 6 months
  • Weight gain of 2 to 4 ounces (57 to 113 grams) per week for 6 to 12 months

Some physicians still use WHO growth as a standard for measuring growth in breastfed and formula-fed babies.

There is quite a variation in the average weight gain pattern. We can divide this into two forms.

  • Banana babies – These babies are lean with increased height. They tend to have high metabolic activity and burn calories faster. Banana Babies grow quickly in height than weight.
  • Apple Babies or Pear Babies – These babies are plumper and have more baby fat than banana babies. They have moderate metabolic activity and gain weight faster than height.

Quit obsessing about breastfed baby weight and growth chart

New mothers are very considerate about their baby’s weight gain.

They tend to measure it frequently. Of course, the baby cannot grow weight overnight. It takes time and many restless nights to breastfeed your baby, and new mothers want to see results quickly. 

Always remember that a growth chart is not an ideal parameter; it’s just a tool to measure the average ratio. So stop obsessing over the growth chart.

Your baby could be doing well; he is alert, oriented, growing at his own pace, and achieving his milestones.

What else do you need? Just monitor his weight every two weeks or every month. Stunted growth or decrease in weight is alarming. Only then do you need to visit your pediatrician.


Are breastfed babies smaller adults?

No, there is no such study that confirmed it. Height, weight, size, body type, and physique are based on different factors like Genetics.

It plays a massive part in the growth and development of the baby. For example, breastfed babies have more IQ and higher intelligence as compared to formula-fed babies. It Is because breast milk contains a higher content of nutrients according to the baby’s demand. 

Are breastfed babies less chubby?

Maybe yes, maybe no. It depends on your baby’s metabolism and latching. Ideally, you should give milk 1/2 ounce per hour to breastfed babies.

This helps them retain enough nutrients in the body. And because they get tired by sucking reflex, providing milk in a small interval is a good idea. In addition, it helps maintain baby weight.

Another factor might include the type of breastmilk you have. Some women have fatty milk others have a bit of watery flow.

Are breastfed babies more attached to mom?

Yes! Various studies are proving that breastfed babies are more attached to their mothers as compared to formula-fed babies. This is because the close interaction of the baby with the mother helps to bond more affectionately.

The baby can have a feeling of being secure, and this is conducive to the development of the baby’s emotional personality. But it also includes the baby’s innate personality behavior and the environment in which he is being nurtured. Breastfeeding is just a minor factor.

Are breastfed babies leaner than formula-fed?

Well, they could be leaner as compared to formula-fed babies because of specific reasons.

– They have to burn more energy in the sucking reflex.
– They feed according to their body’s demand.
– They have an efficient self-regulated metabolism system.
– They latch for a short period.


Babies triple their birth weight within the first year of life, whether breastfed or formula-fed. However, every baby gains weight according to their body type.

You can’t have a set of defined parameters for every baby. Some babies are chubbier other are leaner. Some look like tiny buddhas. Every baby is different.

Obsessing over the growth chart or feeding your baby more than his body needs doesn’t mean that your baby will gain weight. This is not a race to reach for the highest percentile on the growth chart. Instead, focus on your baby’s health and development.

Engage more with your baby. Look for the milestones they have achieved. How active and energetic your baby is. This is the stuff that matters.

However, if your baby shows poor health, stunted growth, and delayed milestones, then talk to your doctor about it.

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As a writer for 1happykiddo, Saumya wants to help new parents and older siblings help raise the newest member added to the family. Her parenting tips come from her experience of being 15 years older than her youngest sibling. When not writing, you can find her reading novels, traveling, and cooking nutritious meals.

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