Why Your Baby’s Poop Changes When Transitioning To Whole Milk

Poop Changes When Transitioning To Whole Milk

For parents, it is a big responsibility to change their baby’s diapers, and honestly, it is not something parents love to do. However, what’s worse than changing diapers, is when parents notice that their baby’s poop has become hard. This typically happens when the baby transition from breastmilk to a milk formula.

Parents often get worried when the baby’s poop changes and wonder whether the transition is normal. It is normal for the poop to change once the baby transitions to cow milk from formula or breastmilk. During this transition, babies might also experience mild constipation because their digestive tract is adapting to this change. However, if, during this transition, the baby has a fever or other symptoms, it’s important that you take him or her to see a doctor.

This article will also discuss why the consistency and color of the poop may change and what you can do to ease the transition for your infant. Read on to learn more about why your baby’s poop changes after transitioning to whole milk. 

How baby poop changes when transitioning to whole milk

The American Academy of Family Physicians states that parents should only feed their baby whole cow milk when they are at least one year old or when they become a toddler. However, what are the steps you should take once your baby switches to cow milk and you notice that their poop is hard?

If you breastfed your baby before the transition to whole milk, you’re most likely used to seeing your baby’s poop being a mustard yellow, green, or brown color with a seedy texture. If you feed your baby formula milk, you probably have seen orange, light brown, and yellow-colored poop. The consistency of this poop is similar to that of peanut butter.

When babies transition from formula to whole milk, you’ll notice that the color, consistency, and size of their poop changes too and this is normal. 

Cow milk is rich in fat, protein, and mineral. Unlike breast milk, cow milk is tougher for your baby to digest. Formula milk is generally made from skim milk that has been highly processed and it has lower protein and fat content than whole milk. 

When the baby starts drinking cow-derived milk, their poop may change in texture and color. You can expect their poop to be tan, pale, and hard in texture.  This happens because your baby’s body is adjusting and adapting to the change of proteins found in the whole milk.

Why do babies get constipated with whole milk?

It is common for babies to have hard poop, especially after transitioning from formula and breast milk to whole milk. 

If you find hard poop in your toddlers’ diaper, it is most likely a sign of constipation caused by milk protein intolerance. Constipation is normal since their digestive system is learning to break down the protein found in whole milk. 

However, if your baby’s stools look like tiny pebble-like poop that’s very firm, it can indicate extreme constipation or dehydration. When this happens, you should not hesitate to bring your baby to his doctor for a check-up. 

Can switching from formula to milk cause diarrhea in babies?

If you’ve just introduced whole milk into your infant’s diet, they may temporarily experience mild diarrhea. This usually indicates that the baby’s digestive system is receiving more protein and their body is adjusting and adapting to this change. This is usually not something to be worried about.  

However, if you’re frequently finding that your baby is having bad diarrhea after transitioning to whole milk, then this is neither normal nor not healthy for your infant and you should reach out to your pediatrician as soon as you can.  

In rare cases, it could be that your baby is allergic to milk.

It’s always best to speak with your pediatrician because your baby may also have an illness or caught a virus that is unrelated to the milk he’s consuming. If your infant is showing signs of illness or has a fever, make sure to contact your pediatrician right away.   

White or yellow baby poop after transitioning to whole milk

Parents spend a lot of time examining the poop of their babies, checking the color, consistency, and texture. While white poop is rare, if it does occur, then you need to visit the doctor. Yellow poop can occur for several reasons, ranging from normal to severe.

If the poop is chalky white, it typically means that the liver has a bile shortage. White poop can also mean that the baby has issues digesting the food. 

On the other hand, yellow poop can also occur when everything is normal, but if the baby poops regularly, and the poop is runny, yellow, and contains mucus, you need to visit the doctor.

A poop that has a bright yellow color is cause for concern as it also occurs due to an underlying illness. If you see your baby’s poop being bright yellow, visit the doctor as soon as possible. 

A common cause of bright yellow poop is an infection in the intestines. During an intestinal infection, the baby might experience:

  • Diarrhea
  • Pain in the abdomen
  • Other symptoms

Baby poop color change after transitioning to whole milk

Poops have several colors, and most of them are considered normal. When your infant shifts to whole milk, the color of the poop may vary temporarily. After shifting to whole milk, the color of the poop will be tan and pale.

If your baby is eating solids, the undigested food can cause the poop to change its color. Baby poop that is healthy could be green, brown, yellow, or orange.

Undigested milk in baby stool

If your infant has problems digesting milk properly, he will probably have watery diarrhea. When you introduce whole milk to the baby for the first time, they consume a different variety of lactose than they are used to. If the baby is having problems digesting that lactose, you may notice the following signs:

  • Upset tummy
  • Bloating
  • Gas
  • Intolerance

Lactose intolerance can cause diarrhea, which is why if you notice the signs, visit the doctor abruptly.

What does baby poop look like with a milk allergy?

The symptoms of a milk allergy vary and can go from mild to severe. This allergy should be taken seriously, and you should see a doctor. If the baby is allergic to milk, he could have red or black diarrhea, which is caused by inflammation in the gut.

The inflammation typically appears in the lower region of the gut. If the diarrhea is black, it is probably caused by inflammation in the upper region of the gut. Symptoms of a milk allergy are:

  • Watery nose and eyes
  • Vomiting
  • Diarrhea
  • Wheezing
  • Itchiness around the mouth 
  • Hives
  • Swelling in the throat, lips, and tongue
  • Shortness of breath
  • Coughing
  • Colic

If you notice these symptoms, then contact your doctor immediately.

How to help baby transition to whole milk

There are several things that parents can do to ease the transition to whole milk for our infants. 

Here are some useful tips to help your baby transition to whole milk:

  • Wait until the baby is at least a year old
  • Take it slow; you can also mix whole milk with breast or formula milk
  • Slowly increase the ratio of the whole milk
  • The milk should not be given as a meal but as a beverage
  • Make sure the milk is warm

Fussy baby after transitioning to whole milk

Babies are generally fussy, and after the shift to whole milk, it is also normal for babies to strain while pooping. You may see babies making faces due to frustration when trying to poop. However, if the crying and fussiness become frequent, the situation is not normal. During this stage, it is important to discuss the baby’s condition with the doctor.

How long does it take for a baby to adjust to whole milk?

Unfortunately, there is not a set schedule for this; all you can do in this situation is give your little one a bit more time so that he/she can adjust. However, the time it takes for the baby to adjust depends upon the amount of milk he consumes and how well the body is responding.

If you follow the recommendations given by the doctor and keep an eye on the signs and symptoms, such as an allergy or an illness, your baby will be fine and healthy and can benefit from consuming whole milk.

The best milk for babies aged two and three

The American Association of Paediatrics (AAP) states that babies over the age of two should be given milk that has a low-fat content. A study in 2013 concluded that babies who consumed 1 % milk had a higher body mass index (BMI) than those that consumed 2 % or whole milk. 

Research also shows that people are usually full after consuming dairy products with high-fat content.

Other sources of calcium other than milk for toddlers

If your toddler is not a fan of drinking milk or having other dairy products, you don’t need to worry, as he can get calcium from these foods:


To get a high intake of calcium, you can feed your toddler this:

  • Almond butter
  • Almonds
  • Canned salmon
  • Chia seeds
  • Tahini
  • Broccoli
  • Kale
  • Bok Choy
  • Sesame seeds
  • Tofu

Vitamin D

To get a high intake of vitamin D, you can feed your toddler this:

  • Fortified Orange Juice
  • Egg yolk
  • Salmon
  • Tuna

Non-Dairy milk substitute for toddlers

Soy Milk

The unsweetened variety of soy milk offers the same amount of nutrition as cow milk and is extremely beneficial for toddlers. However, before giving this milk to the toddler, ensure that he can tolerate soy.


This article will clear up a lot of confusion for you, and you won’t need to worry about the color of your baby’s poop. This article discusses in detail the reason behind the changes that poop undergoes. We have also discussed how you can help the baby shift from formula or breastmilk to whole milk.