The way your body is built, and the way it works, depends on what you choose to eat.
You need food to:
- Supply energy.
- Provide the materials to build and maintain every part of the body.
Energy
Energy needs have first priority.
You body needs energy just to stay alive. Energy cell, tissue and organs needs energy to do its work.
You also need energy to move your body-walking, running, playing games, dancing, doing work.
Grow and maintenance
Your body needs materials to:
- Build new cells during growth.
- Replace and maintain existing cells. All your life, every day, some cells die and must be replaced. Red blood cells live about four months. Some cells live only about two days.
- Maintain the correct chemical balance in body fluids, without which none of the complex chemical reactions in the body could take place.
- Form enzymes, antibodies, and hormones, which are vital to all body functions.
Basic materials for these essential body processes are obtained from:
Food + Water + Oxygen
What's in your food?
There are six different groups of constituents in food, shown in the chat below. They are called nutrients.
When a food contains a high proportion of a nutrient, it is said to be a good source of that nutrient.
All food contains some nutrients. No food contains them all.
You can see that foods vary greatly in the nutrients they supply. A food which supplies protein, minerals, and vitamins, as well as carbohydrates and lipids, is said to have a high nutrient density.
Nutrients
- Carbohydrates (sugars, starches, fibre)
- Lipids (fats, oils)
- Proteins (very complex compounds)
These form the greater part of most foods. They are measured in grams.
- Minerals (simple elements)
- Vitamins (very complex compounds)
These are present in some foods in minute amounts. They are measured in milligrams (mg) - one thousandth of a gram, or in microgram (mg) - one millionth of a gram.
Water
Water is present in all foods and is measured in grams. Some foods contain a lot of water. Some foods contains very little water.
What happens to food?
The chat shows the body gets the nutrients it needs from the food we eat.
The process of eating.
Food
Smell - may stimulate digestive juices
Senses Appearance may stimulate desire to eat
Texture - varied textures enhance the pleasure of eating
Taste - bitter, sweet, sour, salt. Our preference may influence what we chose to eat
Chewed It is important to chew food thouroughly to break it down into smaller particles. Chewing firm foods keeps gums and teeth healthy.
Digested Food is separated into NUTRIENTS. Digestive juices (enzymes) break down the nutrients into smaller units. Food is now changed into invisibly small particles.
Absorbed These particles pass into the bloodstream. The body chooses what it needs for each special purpose.
Cells Waste is excreted from the kidneys and the large intestine.
Energy Growth and maintenance
Nutrients work together
No nutrients can work by itself. All the nutrients work as a team in the body.
Body fluids
Water is essential for life. It forms body fluids in which all activities within the body take place. It is essential both for energy and for growth and maintenance.