Balanced Diet

A balanced diet is a diet that includes appropriate proportions of all the different biological molecules, including carbohydrates, proteins, lipids, vitamins, minerals, dietary fibre, and water. 

Carbohydrates, proteins, and lipids.

We get the majority of the energy we need each day from carbohydrates.

However, lipids are also used for energy, and even proteins can be broken down for energy if necessary.

As in physics, we can measure energy in Joules (J). However, in the case of food, we often use calories instead.

Lipids refers to both fats and oils.

If the lipid is solid at room temperature we can call it a fat, but if the lipid is liquid at room temperature we can call it an oil. 

To provide energy for chemical reactions.

To provide the material for building things, such as organelles and cells.

This means proteins are for important for development, growth, and repair.

Similarities: vitamins and minerals are both essential for healthy growth & required in small quantities.

Differences: vitamins are organic compounds, so are produced by living organisms and made from carbon atoms. Mineral ions are very simple charged particles and are not made by living organisms. 

It is important in maintaining good vision, healthy hair and healthy skin.

Vitamin C deficiencies can lead to scurvy.

Calcium helps to build strong bones.

Vitamin D helps us absorb calcium. We can synthesise (make) vitamin D using sunlight. 

Iron is an important component of haemoglobin. Haemoglobin is the protein in red blood cells that allows them to transport oxygen around the body.

A lack of iron (and hence a lack of haemoglobin), can lead to anaemia - a condition in which we can't transport enough oxygen to our tissues. 

Fibre helps food to move through our intestines, and helps prevent diarrhoea or constipation. 

~70%