Why do we need balanced nutrition for proper growth?

Human Body

Just like your computer, human body is also made up of matter. The smallest particles of all matter are atoms. Two or more atoms joined together form larger particles called molecules.

There are many different kinds of atoms. An element is a substance that contains only one type of atom. Although there are over 100 different elements, only some of them are found in your body. Other elements make up the remaining portion of a human's mass. For example, there are several grams of phosphorus and more than 1000 g of calcium in the body of a typical adult. Elements such as iron and iodine occur in even smaller amounts. Although these and other elements are present in very small amounts, they are still important. Without them, body cannot work properly.

Most of the elements found in the human body are not present in pure form, but are joined together with other elements to form molecules called compounds. For example, most of the oxygen atoms and hydrogen atoms in your body are joined together to form molecules of water. Water is a compound made up of these two elements.

Some of the elements and compounds found in body are used to build or repair body cells. Other elements and compounds supply energy to the cells in your body. Cells are the tiny subunits that make up all living things. Inside cells, many chemical reactions occur. It is these chemical reactions that keep your body alive and active. For the reactions to occur, cells need energy. This energy as well as the substances cells need for growth and repair comes from the food.

Why your body needs food?

Your body is made up of skin, muscle, bone, blood and many other materials. Where do these  materials come from? How does your body repair broken bones or replace blood when your bleed? As you grow, your boy makes new skin and muscle, as well as bone and other types of material. Where does this new material come from? Just as a car needs fuel to run, your body needs energy to power all its activities. Where does your body get its energy?
We get it "from the food we eat". Food contains many different substances. Some of these substances provide you with energy as well as with materials that body needs to grow and repair itself. You are what you eat.
Nutrition
Nutrients in the food you eat contain the many different elements and compounds that your body needs. A nutrient is any material that can be taken into your body cells and that is useful to your body. The nutrients in food supply the energy and the material your body needs to grow and survive.
Nutrition is the study of the nutrients in food and the effect of these nutrients on your health. Sometimes people use "nutrition" and related words to refer to healthful foods or good eating habits. For example, a meal that contains a good balance of  the nutrients body needs is often called "nutritious". If a person practices good nutrition, she or he selects nutritious foods and eats just enough of them to supply the body's needs.
Good nutrition is especially important for a teenager because of the many changes taking place in body. Adolescence is a time of rapid growth and development. Many of  bones grow longer, causing your height and overall size to increase. Muscles also grow larger, increasing strength. Body may produce more fat. Such body growth requires a lot of energy and large amounts of certain elements and compounds. Teenagers need different amounts of nutrients than either children or adults. In addition, no two teenagers have exactly the same nutritional needs.
Human body needs many different nutrients. There are about six nutrients which make a diet balanced. The nutrients in each six are important since they help body grow, repair itself or work properly.