Digestion is the process that breaks food down into the smallest possible parts so that the body can convert it into energy. When we eat, food passes through the oesophagus to the stomach where digestive juices convert food into proteins, sugars and fats. When food leaves the stomach, it passes to the small intestine where it is absorbed as nutrients into the body or passed further along to be expelled from the system as waste. How long it takes to digest a meal depends on what you have eaten. Red meat can take three days to digest while fruits and vegetables pass in fewer than 12 hours.
The body is not able to break down fibre. Foods high in fibre include oatmeal, beans and carrots. Even though the body cannot digest these foods, we still need them. Fibre helps regulate bowel function, which is necessary to cleanse the body. Fruits and vegetables high in fibre can take several hours to digest.
Half of all the protein we consume is used by the body to build and repair cells. About 97 per cent of the red meat we eat is easily digestible---yet, proteins stay in the stomach longer than foods that are considered less digestible, like fibre. Because of the many functions of protein in the body, it can take from one to three days to digest steak, eggs or nuts.
Fat molecules provide a rich source of nutrients to the body. They insulate the cells, provide energy and support the immune system. Essential fats needed for a healthy diet are found in nuts and fish. Like proteins, these foods take longer to digest than those high in fibre since the body uses much of it for energy.
Carbs contain about 40 per cent of the energy needed to feed the body. Most dietary carbohydrates come from cereals, fruits and vegetables. Easily digestible, carbs takes under three hours to pass through the system.
The body's main source of glucose, or energy, comes from starch. This includes foods like corn and potatoes. Digesting these starches could take three to four hours---which is not considered a long time when it comes to digesting food.