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The science of nutrition and healthy eating
The science of nutrition and healthy eating

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1.3 The components of food

The reasons given for eating are many and complex. Everyone probably eats for different reasons at different times of the day and on different days. Ultimately, we need to eat to stay alive, but what do we need to eat?

Our bodies are made up of many tens of thousands of different chemical molecules. The food we eat needs to contain enough raw materials to produce all of these molecules while we are growing, and to repair and replace them once we become adults. Food must also give us the energy we need to live. If we take in lots more food than is needed, the excess can be converted into fat and stored.

On all manufactured food in the UK, you will find a label on the back or side of the packaging (see Figure 3). There is usually a label on the front too, which carries some slightly different information. If you have not already done so, this is a good time for you to start collecting some food labels, which will be used at various stages during the course.

An image of a food label on the back of a pack of ham.
Figure 3 Nutrition information on a typical food label

For now, we will concentrate on the components of food listed in Figure 3 below ‘Energy’. They are not always listed in the same order, so we will start with protein.