What Is Fecal Fat?

Medically Reviewed by Minesh Khatri, MD on September 12, 2023
Written by WebMD Editorial Contributors
3 min read

The last stage of digestion is excretion. When you have bowel movements, you are removing all the material from food that your body couldn't use. Typically, your body has already removed essential nutrients, absorbed them during the digestive process, and is ready to excrete the rest. There are multiple organs that are part of the process, including your stomach, intestines, liver, and pancreas.‌‌

If one of your digestive organs has a problem, it can disrupt the digestive process. You may develop a condition in which your body doesn't get all the nutrients out of your food. Instead of nutrients fueling your body, some of them, including fat, can be passed in your stools.

If you have a condition that makes it difficult to digest fat, you may also develop fatty stools or fecal fat. When this happens, you may experience digestive issues such as pain, gas, or diarrhea. Your doctor will need to do tests to figure out what is causing your fatty stools.

Having too much fat in your stools is called steatorrhea. It's a sign that your digestive system isn't breaking food down enough to absorb it properly. This is known as malabsorption.‌

If you aren't absorbing food properly, it's usually due to a problem with one of the organs in your digestive system. Some of the most common reasons for malabsorption include:‌

  • Intestines failing to absorb nutrients
  • Your pancreas isn't producing enough digestive enzymes
  • Your liver isn't producing enough bile to break down fats in your diet
  • You have another health problem the impacts your digestion

If you have a health issue that's causing malabsorption, you may notice unusual symptoms and changes to your stools. Many of the symptoms of fatty stools are similar to those of digestive distress. Unlike an upset stomach from a virus or food-related discomfort, the symptoms of malabsorption don't get better on their own. They continue and get worse over time.‌

Some of the symptoms of fatty stools include:

  • Frequent greasy, loose stools 
  • Stools that float and are difficult to flush down the toilet
  • Large quantities of stool when you have bowel movements
  • Foul-smelling stools
  • Indigestion
  • Gas
  • Cramps
  • Unexplained weight loss

After a while, malabsorption can lead to malnutrition, loss of body fat, and muscle wasting. Without treatment, you may develop complications such as poor bone health, anemia, or vitamin deficiencies. In children, malabsorption can cause slow growth, neurological issues, and delayed puberty because their body isn't getting enough nutrients.

If your doctor suspects that you have a malabsorption problem, they will do tests to confirm it. Testing for fatty stool is non-invasive, but it will require you to collect your stools. 

Your doctor will give you directions on how to collect stools at home and store the samples. They will then send the samples to a lab for analysis. From this, your doctor can find out how many fat globules are present in the sample.‌

You may only need to provide one sample, or possibly up to several days worth of stools. This will allow them to compare the amount of fat in each sample. Higher than average amounts of fat are a sign of malabsorption.

Your doctor will tell you if you need to restrict your diet while collecting stool samples. There are some medications and supplements that can affect test results, so you should discuss this with your doctor. Using laxatives is discouraged while collecting samples.

Fatty stools and malabsorption are not conditions by themselves. They are symptoms of other health issues. Once your doctor has determined that you are experiencing malabsorption, they will do more testing to figure out the cause. Your doctor will ask you about your medical history and any medications you are taking. They will discuss your diet and lifestyle. All of that information will help them narrow down the cause of your fatty stools.

Conditions that lead to fatty stool and malabsorption include:

  • Liver disease, including biliary tumor or biliary stricture
  • Celiac disease
  • Pancreatic disease, including chronic pancreatitis or pancreatic cancer
  • Crohn's disease
  • Cystic fibrosis
  • Enteritis
  • Small bowel bacterial overgrowth

The treatment for fatty stools and malabsorption depends on the underlying cause. Once your doctor knows why you're having malabsorption, they can begin a treatment plan for you. You may need medication, surgery, or lifestyle changes to manage your condition.