Carbohydates

Carbohydrates are derived mainly from plants, including foods such as fruits, vegetables, pasta, rice, legumes (beans), and other grains fall in this category. Carbohydrates are very important to the body since they are the primary source of energy. Some body tissues, such as red blood cells and most parts of the brain, can only use carbohydrate (glucose) for energy.

Carbohydrates break down into glucose molecules. If intake of carbohydrate is in excess of total energy needed by the body, the excess carbohydrate will be stored as fat.

Fibre is classed as a carbohydrate and is also made up from lots of sugar molecules. However, unlike starches and sugar, digestive enzymes do not readily break down fibre, so it is not a source of ‘available’ carbohydrate and does not contribute to blood glucose levels.

Proteins

Proteins are made up of many small units called amino acids. There are twenty different types of amino acid. Some amino acids that we need can be made by the body, but those that the body cannot make must be provided in the diet. These are the ‘essential’ amino acids. Since most sources of protein do not contain all of the amino acids that we need, it is important to eat a range of protein-containing foods.

Protein can be found in a wide variety of foods including meat, milk and dairy produce, eggs, fish, bread, pasta, legumes (peas, beans, lentils) nuts, seeds and breakfast cereals.

Fats

Fat is an important component of a balanced diet, although we tend to eat far more of it than we need. Dietary fat provides us with essential fatty acids; dietary fat is also needed for the absorption of important fat-soluble vitamins.

Fat is an excellent way of storing energy, but this means that it contains more calories than carbohydrates or proteins. Thus, a small amount of fatty food provides an unexpectedly high number of calories, which is not helpful if you are trying to lose weight.

There are different types of fat – some are beneficial to our health and others can be harmful. The three main types of fat are: saturated, polyunsaturated and monosaturated fat.

Vitamins and Minerals

Vitamins and minerals are essential for health. Some may even have pharmacological properties – i.e. they can help to treat diseases or conditions.

Vitamins are organic compounds and most can easily be destroyed – by cooking or processing foods, for example. Vitamins are named by letters of the alphabet. There are two main groups:

• Fat soluble vitamins such as A, D, E and K
  
• Water soluble vitamins such as B and C
  

Minerals are simple chemical ‘elements’ that are naturally found in water and soil and enter food chains via plants, which take them in by their roots.

If you eat a healthy nutritious diet with lots of variety then you should get all of the vitamins and minerals that you need.

Water

The human body is two-thirds water. Water is essential nutrient that is involved in every function of the body. It helps transport nutrients and waste products in and out of cells. It is necessary for all digestive, absorption, circulatory, and excretory functions, as well as for the utilization of the water-soluble vitamins. It is also needed for the maintenance of proper body temperature.

Water must be continuously replaced since on average 250ml is lost on a daily basis through breathing. Nutritionists have difficulty in suggesting an exact daily requirement because the amount of water required will vary depending on the on the climate and whether any type of activity is undertaken. By drinking an adequate amount of water each day-at least eight glasses (2 litres) -you can ensure that your body has all it needs to maintain good health.