You may be able to munch a sandwich in a couple of minutes but it takes your body a long time to tackle the problem of digesting it. In fact, from eating your lunch to getting rid of the waste material takes an average of 18 hours. As you can see from the diagram, the journey your food takes is quite a complicated one. Essentially, your digestive system is like a series of compartments each with a different role in the digestive process.

Once you have chewed your food and mixed it with saliva, it passes into the oesophagus. The enzymes in your saliva have already started the digestive process and at this point the food has become a soft paste. It gets propelled towards the stomach via the gullet by a series of muscle contractions, known as 'peristalsis'.

Your stomach is a muscular bag closed at the top and bottom by thick muscles that act as one-way valves. The stomach wall contains special muscle fibres that start to churn the food over. Glands in your stomach then secrete acidic gastric juice which turn your food into a liquid. It may surprise you to learn that your stomach secretes as much as three litres of gastric juices a day. Stomach acid, can give rise to common problems such as indigestion or heartburn.

After its stop-off in the stomach, your liquefied food travels to the small intestine via a further process of peristalsis. Your small intestine is actually a tube of muscle six metres long and it is here that water, fat and protein is taken from your food. This part of the digestive process is undertaken by enzymes in the gut wall, as well as by juice from the pancreas and bile from the liver. Next, the contents of the small intestine pass to the large intestine or colon. Although only 1.5 metres long, it’s called 'large’ because it’s much wider than the small intestine. This is where additional water, salts and minerals are removed from your food.

The final stage of the journey is towards the rectum, where waste matter is formed into stools and expelled via the anus.

Your digestive system is a highly tuned system to ensure your food contents travel at the right 'pace' and in the right 'direction' to allow proper digestion. It is not surprising that with all this happening every time we eat, sometimes things go wrong. So, if you suffer from any of the complaints listed on the left, simply click to find out what’s causing your problem - and discover how you can treat it.