Floating Bowel Movement (Stool, Feces) Causes

Your stools can reveal a lot about your health, not only the health of your bowels but even of other systems in the body. The frequency, color, consistency and even smell can vary to indicate a number of health conditions. On a more detailed level, various tests can be performed on stool to identify health problems. However, most of us do not give much thought to whether stool floats or sinks but this fact can differentiate between normal and abnormal stools, which be a sign of disease.

Should stool float or sink?

Healthy stools (bowel movement or feces) usually sink. However, floating stools doe do not necessarily mean that there is a health problem. The reason why something floats or sinks in water is a result of its density. Oil floats on water and most people think that fat in the stool causes it to float. This is not true. The reason why stool floats in most instances is because of intestinal gas which is not passed out as a ‘fart’ (flatus) but rather in the stool.

It is important to understand the composition of feces. Most of it, around 60 to 75%, is made up of water. The rest comprises undigested fiber and other solids (±7.5%), bacteria (± 7.5%), fat (2.5 – 5%), inorganic matter (2.5 – 5%) and protein (usually less than 1%).  Gas does not contribute significantly to the composition of stool but even a slight increase in gas within the stool can make a difference between it floating or sinking. Floating on its own without any other symptoms is usually not a concern and will often resolve on its own even without treatment.

Floating Bowel Movement and Disease

It is difficult to identify floating bowel movement on its own is a sign of some disease. The presence of other symptoms like diarrhea, constipation, abdominal pain, changes in appetite and alterations in the consistency, color and even odor of the stool along with floating bowel movements is more likely to be due to some disease or the other. The problem is usually associated with the digestive system, including the gastrointestinal tract and/or the pancreas, gallbladder or liver.  A stool analysis can also be helpful in identifying abnormalities that are not obvious to the naked eye.

What makes stool float?

The increase in intestinal gas which leads to floating bowel movement is more likely to originate from the colonic bacteria. Some air that may be swallowed during eating, drinking or with breathing can also reach the bowels as well as the gas in carbonated beverages. The process of chemical digestion where gas is released as a byproduct and even gas diffusion from the bowel can also contribute to intestinal gas. However, disturbances with the colonic bacterial (normal intestinal flora) is more likely to contribute to floating stool.

There are a number of reasons why the amount of colonic bacteria may increase, or why the bacteria may produce more gas. Normally the population of this ‘good bowel bacteria’ (normal intestinal flora) is kept in check by a host of factors.  But if the bacterial population increases or food is not fully absorbed, the population and food source of bacteria increase accordingly. As a result more gas is produced.

Certain foods are known to increase intestinal gas production.  These foods include apples, beans, broccoli, cabbage, and a host of other gassy foods especially those high in fiber. However, not every person will experience a significant increase in intestinal gas to result in floating stools.

Causes of Floating Feces

These are just some of the more common causes of floating bowel movement. Many of these conditions will need little medical treatment since dietary and lifestyle measures will suffice. Read more on causes of gas for other conditions where floating stool may be seen.

Bowel Infections

When that pathogenic (disease-causing) bacteria thrive in the gut and multiply rapidly, it can also the normal intestinal flora. This allows some of these otherwise ‘good’ bowel bacteria to grow quickly resulting in an overgrowth. Sometimes antibiotics used to treat bacterial infections can also upset the normal intestinal flora. It ultimately leads to more bacteria which in turn means more intestinal gas.

Food Intolerance

Lactose intolerance is the most common food digestion problem. People with lactose intolerance have a deficiency of the enzyme that breaks down the milk-sugar lactose. As a result the lactose remains in the bowel and allows for bacteria to feed on it with more gas being produced as a result. Maldigestion problems associated with other foods may also lead to a similar problem.

Malabsorption Syndromes

There are a number of different reasons for malabsorption. In these conditions the digestive tract may be able to digest the food but it cannot be absorbed into the body. Inflammation of the bowels is one of the causes and this may be due to a host of conditions ranging from infections and food sensitivities to alcoholism.

Pancreas Diseases

The pancreas produces may different types of digestive enzymes which are released into the duodenum of the small intestine. However, where there are pancreatic diseases then there may be insufficient digestive enzymes to breakdown foods. The nutrients accumulate in the lower bowels and more bacteria can multiply and produce gas.

Gallbladder Diseases

Bile secreted by the gallbladder emulsifies fat so that the fat-digesting enzymes can then break it down further for absorption. When the gallbladder is diseased or has been surgically removed then fat can reach the lower bowels. It is then consumed by bacteria. The stools may be oily or greasy (steatorrhea) but it is the gas production by the bacteria that leads to the floating feces, and not so much the fat.

Short Bowel

The length of the human bowel ensures that sufficient nutrients are absorbed from food. This occurs as food moves through the bowels. However, if the bowels are shorter than normal, adequate digestion and absorption of nutrients may not occur. The bacteria can the produce more gas. This may occur when a portion of the bowel is surgically removed, is missing or damaged from birth.

Other Causes

  • Celiac disease
  • Pregnancy
  • Sudden weight loss
  • Cystic fibrosis
  • Changes in diet


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