Does Baby’s Poop Change When Transitioning to Whole Milk? Why?

Keeping a check on the color, smell, and consistency of a baby’s poop is crucial. A change in any of the three may signal a problem in the baby’s digestive system.

At birth, the meconium stool is dark green, but after breastfeeding for a couple of days, the color changes. Several factors may cause the change in a baby’s poop. For instance, when transitioning to a new diet.

And that leads to the question: does a baby’s poop change when transitioning to whole milk and why?

Hence, Does a Baby’s Poop Change When Transitioning to Whole Milk?

When introducing a baby to whole milk from breast milk or formula, many mothers, nannies, and parents notice a significant change in the baby’s poop.

Often the color and consistency of the stool change. But assuming the transition to whole milk is timely, you should have no cause for worry.

The nutritional composition of breast milk differs from that of whole milk. In other words, breast milk is easier to digest than whole milk. And thus, when introducing the new diet, the digestive system takes a while to adjust to the new diet.

That explains the change in color and stool consistency. However, it should normalize in one week or two. But if your motherly instincts tell you something is wrong with the infant, it’s wise to visit the doctor.

Reasons for a Change in Baby’s Poop when Transitioning to Whole Milk

A baby finds it trouble-free to digest and absorb breast milk. At the same time, infant formula closely mimics the properties of breastmilk.

Breast Milk has fewer fats and a higher concentration of whey protein than casein protein. On the contrary whole milk has more abundance of fats and casein.

When it combines with the acid in the stomach, whey protein changes into an easy-to-digest curd. The high fats and casein protein component of whole milk make it challenging to digest.

Thus, when switching to whole milk, the digestive enzymes take a while to adjust to the difficult-to-digest high casein and fat concentration. As a result, you’ll notice tiny white specks in the baby’s stool.

Under normal circumstances, the digestive enzymes take about one or two weeks to normalize digesting the whole milk. But feel free to contact your doctor if your motherly instincts tell you something isn’t right.

How Poop Changes while Transitioning to Whole Milk

Pediatricians recommend whole milk for babies between the ages of one and two. Transitioning to whole milk usually brings about noticeable changes in the stool.

The difference in stool color, smell, and texture is drastic for babies previously feeding on infant formula.

The changes include the following;


On the first and second days after birth, a baby’s stool is dark. After breastfeeding for a week or so, the stool becomes yellow-orange.

And once you introduce whole milk, the yellowish-orange poop lightens. Unless it grows extra light, there is no cause for alarm.

So, as you introduce whole milk into the diet, monitor the poop color change. But if the poop color lightens so much that it tends to be white than yellow, seek help from your pediatrician.


When feeding on either breast or formula milk, a baby excretes a runny yellow stool. However, during the transition period, the consistency in the poop and frequency drops.

Instead of frequent bowel movements after every feeding, the baby may pass stool once or twice a day only.

Whole milk has a high-fat content. And so, it takes longer time for the baby to digest and hence the less frequent bowel movement.

Constipation or Firmer Stool

Besides stool inconsistency, the high-fat content of cow’s milk affects stool’s nature. It either makes the stool firmer or induces constipation.

For that reason, you better give your baby not more than 16 to 24 oz of milk daily. An intake of fiber-rich foods and fluids also proves helpful.

However, if constipation intensifies and registers the following symptoms, seek medical attention;

  • pellet-like poop
  • Discomfort during bowel movement
  • No stool for 2 or 3 days

In such a case visiting a doctor would help unmask the underlying problem.

Loose Stool

During the first few days following the transition to whole milk, your baby may have loose stool. For that reason, making an abrupt switch from formula or breast milk to whole milk isn’t a wise move.

Instead, increase the baby’s intake of cow’s milk bit by bit. Nevertheless, if the loose stool persists, seek medical attention.


What’s the Best Age for Transitioning to Whole Milk?

The best age for transitioning to whole milk is when your little one is at least one year old.

How Should You Make the Transition to Whole Milk?

The transition to whole (cow) milk should be gradual. That’s because it takes a while for the baby’s digestive system to get used to the whole milk.

So, you can begin by mixing a little bit of whole milk with infant formula. Then as the days go by, increase the ratio till your little one can take whole milk only.

Does Baby Poop Change When Starting Whole Milk?

The introduction of whole milk affects the stool in most babies. The poop may change in color and consistency.

Does Whole Milk Cause Hard Stool?

Whole milk can cause hard stool in babies. For that reason, the baby must take a balanced diet and fluids during the transition from breast milk to whole milk transition.

Does Whole Milk Make Baby Poop White?

Whole milk can make the baby’s poop have white curds in the stool. While still adjusting to processing whole milk, some milk fats may pass undigested and register in the infant’s stool.


As you transition to whole milk from the breast or infant formula, the stool for most babies registers some changes.

The color and consistency of the poop are affected. In some cases, it may even cause constipation or loose stool.

It’s hence wise to make the transition gradual. A better method is to begin by giving the baby a little bit of the milk and increasing the amount gradually.

But in most cases, the changes in the stool normalize in one week or two. However, if you feel something isn’t right with the baby, seek a medical explanation.

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