Why you should breastfeed on demand, according to science

Why you should breastfeed on demand, according to science

Rather than feeding according to fixed times, mums should be feeding on demand. Here's why:

Mums, as you breastfeed your newborn baby, you might think that he never stops feeding. Perhaps it might make you wonder how large – or small – a baby’s stomach actually is. But the size of a newborn’s stomach isn’t as simple as it appears to be… Here’s why – and some extra tips on how to tell if baby is still hungry after breastfeeding.

Why you should breastfeed on demand, according to science

Science is challenging these standard beliefs about a baby’s stomach size. 

Why Baby’s Stomach Size Doesn’t Matter

Mums, have you ever asked yourself this question: If my baby’s stomach is this tiny, why is he always hungry and latched on? 

Now, we know that breastfeeding is more than just nourishment – it’s about love and comfort too. But is it true that all newborns have tummies the size of cherries? Or that all one-month-old babies’ stomachs are the size of eggs? Science says no. 

how to tell if baby is still hungry after breastfeeding

Different babies probably have different stomach sizes. | Image source: stock photos

What Science Says

While many birth educators frequently demonstrate the size of a newborn’s stomach by using a marble, it might not be true. A marble can only contain 5 to 7 millilitres of fluid.

Studies indicate that in general, a newborn baby’s stomach is around the size of a ping pong ball, and  can contain about 20 millilitres of fluid.

A review conducted in 2008, which was published in the Journal of Human Lactation may explain why. In fact, the review reveals that scientific literature lacks any well-grounded studies that reliably define how big infant’s stomachs are. 

In truth, there is no definitive answer as to how big a newborn baby’s stomach size actually is. Newborn babies enter the world with many differences in size – some are small, while others are big. The same variation in size is true for their stomachs, too.

And it’s not just stomach size that determines a baby’s appetite and nursing frequency. How well a baby latches on, his stomach’s flexibility and how long it takes to digest food all affect an infant’s appetite, too.

When it comes to a stomach’s flexibility, physiological movements – like digesting milk – also need some time to develop properly. Science has long backed this up. It has been observed that baby stomachs improve – in terms of relaxing their muscles – within a few days. This lets newborn stomachs expand better and hold more fluid.

What’s the Best Way to Feed a Baby Then? 

Feeding based on times between feeds may not be so wise considering that we don’t know exactly how large an infant’s stomach is. It’s entirely possible for one infant to remain full for a few hours, while another may need extra feeds. 

The ideal way to ensure that they’re not hungry, then, should be by watching for your baby’s hunger cues and feeding on demand, even if it means feeding multiple times within the hour. 

This approach is also recommended by the American Academy of Pediatrics and La Leche League International. 

Interestingly, feeding on demand isn’t a new realisation. Even women who are part of hunter-gatherer tribes used the same method.

Researchers studying the !Kung hunter-gatherers of Namibia and Botswana noticed that during daylight hours, the women breastfed infants between 12 weeks and 2.5 years old a whopping four times an hour. Each breastfeeding session repeated roughly 13 minutes after the other.

how to tell if baby is still hungry after breastfeeding

It might be exhausting, but that cute smile and pure happiness makes it all worthwhile. | Image source: stock photo

How to Tell If Baby Is Hungry? 

There are many ways you can tell if a baby is hungry for breastmilk, such as when they:

  • show rooting reflexes (your baby will open their little mouth and nuzzle against you, looking for your breast, or start sucking on whatever they can find) 
  • cry or become fussy
  • move their heads from side to side 
  • open their mouths 
  • stick out their tongues 
  • place their hands and fists to their mouths 
  • pucker their lips as if sucking 


  • …wait until baby is really hungry and screaming before you nurse him. He may be too agitated to eat properly. Crying will also exhaust him. It may send him to sleep the moment he is on your breast.
  • …worry if the baby doesn’t nurse every two to three hours. You’re looking at a routine, not a strict schedule. As long as you keep an eye out for those hunger cues mentioned above, a regular feeding schedule should fall into place.
  • …worry that your baby is starving or doubt if you are producing enough milk. Frequent feedings will signal your body to produce more milk. If you’re really concerned, keep an eye on two things: diapers and weight gain. If your baby is gaining weight and soaking five or six diapers a day, he’s doing just fine.
  • …overfeed your baby if he’s full. There are many obvious signs including slow, uninterested sucking or turning away from the breast. Stop the feeding once these signs appear and do not force the baby to drink more.


References: ResearchGate, NCBI, Sciencenews.org

Also read: 

My baby is hungrier than usual. Is this a feeding spurt?

4 essential routines for your sweet baby

5 Reasons why your child is always hungry

The basics of breastfeeding – top 10 questions for new parents

Mixed feeding: Everything you need to know

How can you tell if your baby is ready to feed?