Medically reviewed by Natalie Butler, R.D., L.D. — Written by Jayne Leonard on October 1, 2017
Digestion is a process where the body breaks down food into smaller particles to absorb them into the bloodstream.
Complete digestion of food takes anywhere between 24 to 72 hours and depends on several factors, including the type of food eaten and the presence of digestive issues.
This article looks at the digestive process and potential digestive problems and recommends ways to improve digestion.
Share on PinterestOn average, food takes 6 to 8 hours to pass from the stomach and small intestine to the large intestine. From there, it may take over a day to digest further.
In many cases, the food moves through the stomach and small intestine within 6 to 8 hours. It then passes to the large intestine (colon).
However, the exact time varies and depends on factors such as:
- Amount and type of food eaten: Protein-rich foods and fatty foods, such as meat and fish, can take longer to digest than high-fiber foods, such as fruits and vegetables. Sweets, such as candy, crackers, and pastries, are among the fastest foods digested.
- Gender: A 1980s study found that the transit time through the large intestine alone was 47 hours for women and just 33 hours for men.
- The presence of digestive issues: Crohn’s disease, diverticulitis, and irritable bowel syndrome are some of the conditions that may slow down digestion.
Once food reaches the large intestine, it may remain there for up to a day or more as it undergoes further breakdown.
It’s a commonly held belief that digestion only takes place in the stomach. In fact, there are three separate stages of digestion:
Oral stage of digestion
Chewing food breaks it down into smaller particles and mixes them with saliva. An enzyme present in saliva, called amylase, acts on carbohydrates in the food to break them down. The food particles can then form a soft mass that’s easy to swallow, known as a bolus.
Gastric stage of digestion
In the stomach, an enzyme called pepsin helps to break down proteins into smaller particles. Stomach acid also plays an important role in preventing food-borne illness as it kills any bacteria or viruses that may have been present in the food.
Intestinal stage of digestion
Nutrients and water that have been removed from the digested food pass through the walls of the small intestine. They enter the bloodstream and travel to various areas of the body where they are used to repair and build.
The unabsorbed and undigested food that remains then moves to the large intestine. Here, some more nutrients and water are absorbed. The remainder is stored in the rectum until it leaves the body through a bowel movement.
To enjoy a healthy digestive system and to prevent constipation and diarrhea, try the following:
Eat a balanced diet
Share on PinterestPlant foods that are sources of fibre, including apples, legumes, and whole grains, may aid healthy digestion.
Fiber-rich foods, including fruits, vegetables, legumes, and whole grains, help move food through the digestive system more rapidly. They also help prevent constipation, feed gut bacteria, and help with weight loss.
Meat, particularly red meat, is hard to digest so should be eaten sparingly.
Processed and fast foods are often high in fat, making them difficult to digest. They are also rich in sugar, which may upset the balance of bacteria in the gut.
These types of food also contain additives that can cause stomach upset in some people and contribute to poor health.
Stay hydrated
Drinking enough water and other liquids, such as teas and juices, can prevent constipation and keep food moving through the digestive system.
Take probiotics
Probiotics are beneficial bacteria that help restore the balance of bacteria in the body by reducing the growth of harmful bacteria in the gut. The following foods are rich in probiotics:
- natural yogurt
- kefir
- sauerkraut
- kimchi
- miso
- fermented vegetables
Probiotics are also available in supplement form.
Make sure to include fiber-rich and prebiotic-rich foods to feed the probiotics you ingest as well as the healthy bacteria already in your colon.
Regular physical activity
Engaging in daily exercise benefits the digestive tract, as well as the rest of the body. Some people find that a gentle walk after meals reduces bloating, gas, and constipation.
Stress management
Being stressed can slow down digestion and contribute to symptoms such as heartburn, cramping and bloating. To reduce stress levels, engage in meditation, deep breathing exercises, and yoga. Even a few simple deep breaths before you eat can help. It is also important to get enough sleep every night to reduce stress and aid digestion.
Dental hygiene
As digestion begins with chewing in the mouth, problems with the teeth can interfere with this important step. Older adults, in particular, can be affected by improper chewing techniques due to dental issues. Brush and floss the teeth daily, and visit a dentist regularly.
Digestive enzymes
People with low stomach acid, chronic stress, digestive diseases and other conditions may benefit from taking supplements containing digestive enzymes. While these are freely available from health stores, it can be helpful to discuss enzyme supplementation with a doctor first.
Manage digestive conditions
Several medical conditions can cause problems with digestion. People with these conditions should always work with their doctor to manage their symptoms and reduce digestive distress.
Share on PinterestSuffering from gastro‐esophageal reflux disease, or GERD, may affect digestion. If digestive problems are persistent, a doctor should be consulted.
Possible digestive problems include:
These conditions can cause issues with digestion, and contribute to symptoms such as heartburn, bloating, constipation, and diarrhea.
Those who regularly experience symptoms of poor digestion, such as gas, bloating, constipation, heartburn, or diarrhea, should see a doctor who can rule out any serious conditions.
If anyone experiences any of the following symptoms, they should see a doctor immediately:
- rectal bleeding
- significant weight loss
- fever
- persistent vomiting
- feelings of food blockages in the food pipe
Digestive symptoms that get progressively worse or change abruptly also require medical attention.
The time it takes to digest food varies between 24 and 72 hours and depends on several factors. To enjoy optimal digestion, eat a balanced, high-fiber diet, engage in regular exercise, reduce stress, and manage any digestive conditions that may be present.
If symptoms of digestive distress are severe, persistent, or change over time, it is important to see a doctor.
Last medically reviewed on October 1, 2017
- GastroIntestinal / Gastroenterology
- Nutrition / Diet
A white circle with a black border surrounding a chevron pointing up. It indicates 'click here to go back to the top of the page.'
Eating a diet rich in fruits and vegetables can help improve your digestion. pixelfit/ Getty Images
There is no overestimating the importance of digestion: It helps us turn food into the water and nutrients we need to power and maintain our body's functions.
While the overall process of digestion is similar person to person, factors such as gender, age, and medical conditions can change how quickly food is digested.
Here's what you need to know about how digestion works, how long it takes, and when you may need to speed up the process.
It takes between four to six hours for your body to digest food, says Craig Gluckman, MD, a gastroenterologist at UCLA Health.
This is the amount of time it takes for the food to go from your mouth to your colon, also known as the large intestine. However, it can take anywhere between two to five days for food to move through the intestines and leave the body entirely.
There are a few factors that can influence digestion:
- Gender. Women tend to digest food slower than men, and certain digestive conditions are also more common in women. Irritable bowel syndrome occurs two to six times more often in women, and inflammatory bowel disease is twice as likely.
- Age. Digestion can naturally slow as people get older, says Gluckman. This can also increase the risk of acid reflux and constipation in older adults.
- The food you ate. Simple carbohydrates, like white bread, digest faster than food with complex sugars and high fat or protein, like peas and whole grains, says Gluckman.
- Pregnancy. Pregnant people produce higher levels of progesterone, which can slow the digestive system. As the uterus grows, it can also apply pressure to or block parts of the digestive system, like your colon, slowing the digestion process down even more.
The goal of digestion is to provide the body with the nutrients it needs to function. Much of this absorption occurs in the small and large intestines, says Marc K. Taormina, MD, a gastroenterologist at Midwest GI Health.
Including the small and large intestines, the digestive process stretches throughout much of the body and includes these organs:
- Mouth. The entry point of your digestive system uses the teeth and saliva to break down food into a smaller, more easily digestible form.
- Esophagus. The muscles contract and push the food down towards the stomach. At the bottom of it, a muscle called the esophageal sphincter relaxes to let food into the stomach before contracting again to prevent acid from going into the esophagus.
- Stomach. A combination of acid and enzymes further breaks down food in the stomach.
- Small Intestine. At 22 feet long, the small intestine is over three times the length of a person's body. Here, enzymes from the pancreas and bile from the liver break down food again. Water is digested into the small intestine's walls, and nutrients are absorbed into the bloodstream. Food can stay in the small intestine for two to six hours.
- Large Intestine. Waste leaves the small intestine and enters the five-foot-long large intestine. Waste enters as a mostly liquid but, over the course of its 36-hour journey through the large intestine, it becomes more solid. Once the colon fills with stool, it empties into the rectum.
- Rectum. The rectum is an eight-inch chamber that holds stool and alerts the brain that it's time to use the bathroom.
You can't do much to speed up your digestion, nor should you try to. Sped-up digestion may stop you from absorbing all of your food's nutrients, says Taormina. It's important to remember that digestion speed and metabolism are two different things. Speeding up your metabolism to burn calories is a separate process.
The only time you should try to speed up your digestion is under the doctor's advisement and guidance. This may happen if you have irritable bowel syndrome or inflammatory bowel syndrome, says Gluckman.
While you can't speed up your digestion, you can ensure your digestive tract is working smoothly by eating a healthy diet. Here are five tips to improve your digestion:
- Eat more fruits and vegetables, especially apples, raspberries, and broccoli, which are good sources of fiber — a nutrient essential for gut health and known to ease constipation.
- Choose whole grains, like whole-grain bread, oatmeal, brown rice, and quinoa are also good sources of fiber.
- Drink more water, as dehydration can exacerbate constipation. Women should aim to drink at least 2.7 liters a day and men 3.3 liters.
- Reduce your intake of added sugars, like those found in cookies and pancakes, which can harm the healthy gut bacteria essential for digestion.
- Try probiotics, which are foods or products containing colonies of healthy bacteria naturally found in our gut. Probiotic-rich foods include kombucha, kefir, and yogurt.
It takes food about four to six hours to digest through the body and into the large intestine, where it then sits for 36 hours as it makes its way to the rectum.
Factors such as age, gender, and pregnancy can decrease this speed. However, there is no reason for trying to speed up digestion unless instructed by a doctor.