A food pyramid provides a guide to a healthy balanced diet. It shows how to classify food types into different levels. A balanced healthy diet will include servings from each level of the food pyramid and will show the correct quantities you need to eat:

• You need to eat a little of the food at the top (oils, sweets, etc.)
• The food in the middle of the pyramid, fruit and vegetables, must also be eaten in fair amounts.
• You should eat less meat, chicken, fish and other proteins than vegetables and fruit.
• You need to eat more of the food at the bottom of the pyramid (breads, pastas, rices, etc.).

Here is an example of a food pyramid:

Some people eat a very unhealthy diet and turn the food pyramid upside down! They eat far more sweets, cakes, fatty rich food and far less vegetables and starches!

There are many causes of a poor diet.

1. Diseases and infections: When someone has a chronic illness, such as HIV/AIDS, they are sick for a very long time. Their bodies become weak and they cannot take in nourishment from the food they manage to eat, resulting in a poor diet.
2. Dietary practices: In many countries, people have a preference for certain foods, for example rice, samp or mealie meal. People eat a lot of this particular food type and do not get enough protein or fats and oils in their diet. They also often cannot afford other food types, especially in developing countries. However, some families in developed countries do not eat enough fruit and vegetables out of choice and eat a lot of refined carbohydrates which also leads to disease and illness.
3. Poverty and high food prices: Poverty and high food prices stop many people from enjoying foods such as milk, meat, poultry (like chicken) and fruits. This has made it almost impossible for poor families to afford certain food groups. Some families can only afford one type of food group.
4. Food shortage: Sometimes famine occurs in a country where drought, poor farming knowledge and skill, and a lack of technology limits the yield of crops and herds of animals. This results in a food shortage in that country.

In these situations, people will eat whatever food is available to them, often leading to an unhealthy diet.

An unhealthy diet can lead to many health problems because the body does not get the right amount of the different food groups and therefore cannot function properly.

Often we get diseases and conditions because our bodies do not get the necessary nourishment. Some of these diseases are:

• Tooth decay: When you eat or drink too much sugar, the bacteria in your mouth makes acids that eat away at the tooth surface (called enamel), and causes cavities to form.

• Rickets: This is a condition mostly seen in babies and children. When children do not get enough fruit and vegetables and do not get enough Vitamin D, their bodies cannot absorb calcium and they cannot grow strong bones.
• Constipation: This is a painful condition (not a disease) that occurs when bowel movements become difficult and take place days or even weeks apart. An unhealthy diet is often to blame, but there are other causes too. The best way to treat constipation is to eat a healthy diet with lots of fibre in the carbohydrates, to exercise regularly and to drink plenty of water.
• Obesity: This is a condition (not a disease) where a person's body weight is more than \(\text{20}\)% that of the average weight for other people the same age and height as that person. The best prevention for obesity is to follow a healthy, balanced diet.

• Diabetes: This is a disease that affects the body's ability to use blood sugar for energy. Diabetes symptoms may include an increased thirst and urination, blurred vision and excessive tiredness.

• Anorexia nervosa: This is life-threatening eating disorder where the patient starves themselves and deprives their bodies of nourishment to cause themselves to lose tremendous amounts of weight.
• Kwashiorkor: This is a disease that affects many children. It is a lack of protein and iodine in their diet. Children suffering from this may have swollen hands and feet, and especially a very large tummy, many ulcers on the skin and their hair might discolour.