What is food

Food makes your body work, grow and repair itself. The kind of food you eat can affect the efficiency of these processes. Body function and the food that sustains it is infinitely complex. Food is in fact one of the most complicated sets of chemicals imaginable.

Getting to know which nutrients are in which foods can help you to understand something of this complex relationship between your food and your body.

Chemicals in food

Food is composed of many different chemical substances - 'macronutrients' "major nutritional components that are present in relatively large amounts, such as protein", 'micronutrients' "major nutritional components that are present in relatively small amounts, such as vitamins", water, and roughage (dietary fibre). Many other components can also be present in food (see Figure 1).

The chemical nature of food is changed by storage, preservation and, especially, by cooking. Food chemicals can also interact amongst themselves within the body. The way in which carbohydrate is absorbed from the bowel depends to some extent on the presence of dietary fibre, even though the fibre itself is not absorbed.
For example, the availability to the body of iron from plant sources depends on the amount of vitamin C present in the food eaten.