FOOD AND NUTRITION
Calories Food gives the body the energy it needs for everything it does, from repairing damaged cells to sleeping. A calorie is a measure of the amount of energy a food can produce. The body changes the calories in food to energy.
When a person eats more food than the body needs, the body changes the extra calories into fat. Eating less food than the body needs will cause a person to lose weight.
The number of calories needed by a person each day depends on how much energy a person's body uses. For example, an active child usually needs more calories than an adult who works at a desk.
Nutrients Food also provides the nutrients that the body needs to function and maintain itself. These nutrients are proteins, carbohydrates, fats and oils, minerals, vitamins, and water.
Proteins Proteins are needed for body tissue to grow and repair itself. People can get the protein they need from animal sources such as meat, fish, poultry, and eggs and from plant sources such as beans, peas, nuts, and breads.
Carbohydrates Carbohydrates give the body most of the energy it needs. Starches and sugars are carbohydrates. Starches are found in foods such as rice, potatoes, wheat, and corn. Sugars are found in honey and other sweet foods.
Fats and Oils Fats and liquid fats called oils are sources of energy that the body can store. The body uses fats to maintain its temperature and to cushion organs. Fats also make up part of all human body cells and help the body use certain vitamins. Although fats are important to the body, they can also be harmful.
For example, saturated fats that come from meat can raise the level of cholesterol in the blood. Cholesterol is a natural, waxy substance made by the body. It helps to form digestive juices and does other important work. However, when body cells cannot absorb any more cholesterol, the extra begins to build up in the walls of the blood vessels, gradually narrowing them. This condition may lead to a heart attack or stroke.
MINERALS Minerals serve a variety of purposes. Calcium, for example, builds bones and teeth and helps to clot blood. It can be found in milk and hard cheese. Another mineral, iron, is needed to build red blood cells and carry oxygen from the lungs to other body cells. Good sources of iron include meat, egg yolks, and dark green vegetables. Other minerals important to the human body are iodine, magnesium, phosphorous, copper, sodium, potassium, and zinc.
Vitamins The body also needs vitamins. Vitamin C keeps gums healthy and helps the body absorb iron. Vitamin D works with calcium and phosphorus to make strong bones and teeth. Other vitamins are A, E, K, and the B-complex vitamins.
Water Water is important in many chemical reactions in the body. Water also helps the body get rid of wastes and maintain its temperature. Water makes up about 60 percent of an adult's body weight.
FOOD PYRAMID Scientists have created a chart called the food pyramid to show how much of different groups of food a person should eat in order to be healthy. In general they recommend that people eat more grains, vegetables, fruits, and milk and fewer fats and oils.
People should try to eat several servings of grains, vegetables, fruits, dairy products, and meat …