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Diet and Gastrointestinal Diseases


Many people are confused about diet and gastrointestinal diseases. With some conditions, dietary modifications are a vital part of successful treatment. For other gastrointestinal problems, no specific dietary changes are needed. This does not mean that diet is unimportant. It is always important to follow a healthy diet and many Australians need to make changes to their meals and snacks to achieve this. Following are a few simple guidelines to help sort out the facts from the fallacies.

The Basics Of A Healthy Diet

Good nutrition is essentially simple. Australia has one of the most abundant and varied food supplies in the world so it is not difficult to choose a healthy diet from these foods. Claims that foods can no longer supply nutrients for people living in a stressful world are wrong. In spite of the abundance of foods, many people do not make wise choices. Nothing need be forbidden in a healthy diet but some foods should dominate the diet and others play only a small role. The basic principles of a balanced diet are:

  • EAT MOST: Vegetables, Fruits, Grains, Breads and Cereals (preferably wholegrain), Seafoods.
  • EAT MODERATELY: Lean meat or poultry, Eggs, Milk, Cheese, Yoghurt
  • EAT LEAST: Fats, Sugars, Salt and Alcohol.

If you choose most meals and snacks from the foods which should form only a small or moderate part of the diet, your diet will not be balanced. You may still get enough vitamins, but you will almost certainly have too much fat and not enough fibre. Examples of healthy choices for meals and snacks:


  • Fruit
  • Cereal with Milk
  • Toast

For minimum fat and maximum fibre choose: fruit rather than juice; wholegrain or bran cereals such as Bran Flakes, Guardian, All-Bran or Sultana Bran with low fat milk; wholemeal, wholegrain or high-fibre toast with a low fat spread.


  • Sandwiches or bread rolls or toast
  • Salad or Vegetables plus bread or rolls
  • Salmon, Tuna, Chicken, Turkey or lean meat
  • Soup Legumes such as Baked Beans or Pea Soup
  • Fresh fruit Milk or Yoghurt

For minimum fat and maximum fibre choose: wholemeal, wholegrain or rye breads or rolls rather than white; plenty of vegetables or salad (use a low kilojoule dressing if desired); high fibre soups such as pea, vegetable and barley; legumes of any type; fruit; low fat yoghurt.


  • Plenty of vegetables
  • Rice, pasta or grain (such as cracked wheat, barley or corn)
  • Fish, chicken, lean meat or a vegetarian alternative
  • Dessert of fruit (fruit salad, baked apple, fresh raw fruit)
  • Bread or rolls

For minimum fat and maximum fibre choose: large serves of vegetables; brown rice; wholemeal pasta or wholegrain products; fruit; wholemeal bread.


  • Fresh, dried or frozen fruit
  • Breads, muffins, raisin or fruit loaf
  • Wholegrain crispbreads
  • Wholegrain cereals (Sultana Bran)

Note: Wholemeal bread has similar nutritional value to wholegrain, but has broken up grains – both are high in dietary fibre; multigrain is white bread with added grains and had less fibre than wholemeal; rye breads have varying fibre content, depending on the proportions of rye and wheat flour; high fibre white bread is white bread with added oat, barley and legume fibre – it has more fibre than plain white bread but less than wholemeal.

Distribution Of Foods

It is best to distribute foods throughout the day rather than skipping breakfast, skimping on lunch and then eating most of your food at dinner and in the evening. “Small and Often” makes better sense than alternating fasting and bingeing. Most people become quite indiscriminate about what they eat when they are very hungry and those who deliberately restrain their eating to extremely small meals eat more later. It is also important to chew foods well as this gives a good start to the process of digestion.

Food Combining

There is no need to worry about food combining. Contrary to popular belief, the body can digest proteins and carbohydrates eaten together. If this were not so, we would not be able to eat cereals, grains, bread, seeds, nuts, legumes or milk since all these foods contain carbohydrate and protein within the same food. Nor do we need to worry about whether foods are “acid” as the body regulates its own acid:base balance, irrespective of what we eat.

Dietary Modifications

Except in special circumstances, most dietary modifications should fit in with the basic principles of a healthy diet. However, if you need to avoid certain foods because of a specific medical condition, you may need to eat more of other foods to provide the missing nutrients. Supplements are not usually necessary unless there are whole classes of foods you cannot eat.


A restricted diet is much less likely to provide a full range of nutrients. As far as possible, try to include a wide variety of nutritious foods. This will give you the vitamins, minerals, amino acids, dietary fibre, essential fatty acids and other essential nutrients you need for good health. A lack of variety can lead to a poor diet and this cannot be fixed with supplements.

The Digestive System

In The Mouth
Digestion begins in the mouth as foods are chewed and mixed with saliva. Enzymes in saliva begin to break down some complex carbohydrate (also called “Starches”). Chewing food thoroughly is essential for good digestion. As we swallow, muscular contraction moves food down the oesophagus to the stomach.

In The Stomach
The cells lining the stomach produce acidic gastric juices which contain some enzymes to begin breaking down protein into smaller pieces.The mass of food in the stomach is churned by the stomach acid to a soupy consistency, ready to pass to the small intestine. Alcohol and some drugs can be absorbed directly from the stomach but most of the mass of food passes through to the small intestine. Carbohydrates eaten on their own tend to leave the stomach quickly. Proteins and fats delay the emptying of the stomach and so make you feel more satisfied after eating. If you consume large quantities of fat, the mass of food will take many hours to leave the stomach and may produce an unpleasant feeling of “fullness”.

In The Small Intestine
Most of the digestion of foods and the absorption of nutrients occurs in the small intestine. Here juices from the pancreas neutralise the acid from the stomach. Enzymes from pancreatic juice and intestinal secretions break down carbohydrates, proteins and fats. The liver also produces bile which is stored in the gall bladder until it is needed in the small intestine to help digest fats. Once the various food components have been digested in the small intestine, they are absorbed into the bloodstream and go to the liver. From the liver, the nutrients are distributed to the body and provide kilojoules of energy to all body cells. Dietary fibre and some of the complex carbohydrates are not digested in the small intestine and pass to the large intestine.

In The Large Intestine
Bacteria in the large intestine break down many types of dietary fibre and any carbohydrates which have escaped digestion in the small intestine. During this bacterial digestion, more kilojoules of energy are made available. Most dietary fibre is broken by these helpful bacteria but some types are totally undigested and are eventually excreted. The bacteria themselves multiply by the million as they digest fibre and carbohydrates and they contribute to the faecal material which is excreted. A large amount of water is reabsorbed from the large intestine. if this does not occur, diarrhoea results.