Our bodies need a variety of chemical substances, nutrients, to provide energy and function properly. Nutrition is our consumption and use of foods to provide these substances.
There are five nutrients our bodies need to have: carbohydrates, fats, proteins, vitamins, and minerals. Carbohydrates are found mainly in starches, such as bread and pasta, and sugars and provide the body with energy. Fats, whether animal, such as butter or cheese, or vegetable, such as olive oil or nuts, also provide energy. Meat, fish, nuts, and dairy products are sources of protein which our cells use for growth and repair. Vitamins, such as A and C, and minerals, such as calcium and iron, are essential for proper functioning of our internal systems, such as the nervous system and bones. The two non-nutrients we need are water, which cells use to process the nutrients, and fibre, which aids digestion.
The various traditional diets followed around the world typically provide a good balance of these items from local food sources. The amount of food needed to meet this balance will depend on the age and sex of the person, their physical activity level, and their metabolism. An average man will need 2,700 calories each day; a woman 1,900; a 16-year old boy, 3,200; and a 16-year old girl 2,100.
When the body does not receive or utilize the proper amount of these nutrients, various diseases may result. Malnutrition, not consuming enough nutrients, can occur anywhere in the world and is the cause of more than half the deaths of children under 5 in developing countries. Lack of a specific nutrient can lead to such diseases as rickets (soft bones due to lack of Vitamin D), scurvy (a fatal disease affecting the whole body due to lack of Vitamin C), and heart disease (blockage of the blood carrying passages due to too much fats).
