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A healthy diet
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Food gives you energy and the materials to grow and repair your body. A balanced diet has the right amounts of each nutrient.
The seven food groups
Each part of a diet has a job.
How much energy?
Energy in food is measured in kilojoules (kJ). Food labels show the energy per 100 g.
The energy you need depends on your age, size, sex and how active you are. Pregnant women need extra energy.
If you take in more energy than you use, the extra is stored as fat.
The energy you need depends on your age, size, sex and how active you are. Pregnant women need extra energy.
If you take in more energy than you use, the extra is stored as fat.
When the diet is unbalanced
Obesity: too much energy over a long time; linked to heart disease and type 2 diabetes.
Starvation: too little food, so the body breaks down its own tissues.
Deficiency diseases: caused by a lack of a vitamin or mineral.
Starvation: too little food, so the body breaks down its own tissues.
Deficiency diseases: caused by a lack of a vitamin or mineral.
A snack bar has 1800 kJ per 100 g. A bar weighs 30 g. How much energy does it contain?
- Energy per gram = 1800 ÷ 100 = 18 kJ
- Energy in 30 g = 18 × 30
Answer: 540 kJ
A balanced diet has carbohydrates, lipids, proteins, vitamins, minerals, fibre and water. Energy needs depend on age, size and activity. Too much energy leads to obesity; too little to starvation; missing vitamins or minerals cause deficiency diseases.
The interactive lesson includes the diagrams for this topic.
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