Nutrition Facts

Nutrition [nōō-'trĭ-shŭn]

The science of food and how it impacts your body.

Why You Need Food

A Teacher with three children

Nutrition is the science or study of how your body uses nutrients. Just like a car, your body needs fuel to work properly. The food you eat contains substances called nutrients that provide the energy (fuel) for your body to make new cells, heal, fight illness, grow, play and work.


Here are the 6 kinds of nutrients that provide your body with what you need to think, play and work properly.

Variety of raw beef steaks

Proteins are used by the body for growth, and to help build and repair cells. Proteins also help keep muscles, skin, hair, and nails healthy.


Carbohydrates are the main source of energy for your body. Some carbs like sugar give you quick energy. Other carbs such as starches give longer-lasting energy.

Olive oil and olives in bowls

Fats and Oils are used to help the body store vitamins and build tissue to protect important organs. Fats are also used by the body as a "backup" fuel system.

Vitamins are needed to help the body use carbohydrates, fats, and proteins and to help its systems function. Many kinds of vitamins are essential to your diet.

Minerals are used by the body to build new cells and control important body processes.

Water dissolves some vitamins and helps bring nutrients to the cells in your body. Water also helps you swallow and digest foods, and helps keep your body temperature normal.

There is no single food that can supply all the nutrients your body needs to stay healthy. That's why it's important to include a variety of foods in your diet.

DIET? I'm Not On a Diet!

Get in my belly, burger. An obese young man about to eat a huge hamburger.

Think again! Your diet is everything you eat and drink. The question is — is it a healthy or unhealthy diet? A healthy diet is a balanced diet that includes healthy portions from all of the food groups.

The Food Pyramid Guide has been changed to MyPlate. To build a healthy plate of food, choose enough fruits and vegetables to cover one-half of your plate. Then make your grains and protein fill the other half. And be sure to drink a lot of milk to keep your bones and teeth strong and healthy. MyPlate makes it easy to get the nutrition that you need and with very little effort.

So how much is a serving?

You may be eating good foods each day, but still are not as healthy as you could be because of the amount of food you eat. How much food you eat can be as important to your good health as what you eat.

Whole baked chicken with vegetables

Many of the portions that we eat today are much larger than the recommended "serving" size. Look at what is considered to be a serving size: in general, 1 slice of bread, 1 cup of ready-to-eat cereal, or 1/2 cup of cooked rice, cooked pasta, or cooked cereal can be considered a 1-ounce equivalent from the grains group. Ideally, 1/2 of those grains should be whole grains.

Check out these charts from to see how much you should eat:

What is a healthy diet?

group of happy kids or friends playing outdoors

A healthy diet provides all the nutrients we need in a day. The amount a child needs from each food group depends on age, gender and daily physical activity. Children who are very physically active, for example, need more than children who get little or no physical activity.

Why is water so important?

Boy drinks water from bottle outdoors sitting on stone

Water is the most necessary nutrient of them all. People can't survive for more than a few days without it. Your body is approximately 70% water. You lose precious water each day in your normal activities of breathing, sweating, and other things. Your blood is mostly water, which is how it moves nutrients and oxygen to all of your cells. In addition, water helps to lubricate your joints, helps you fight infection, and helps your memory — just to name a few. So drink up, drink lots, and drink often. Learn more about keeping healthy with water here.

Quick Tips to Healthy Eating:

Homemade whole grain bread
  • Make half your grains whole grains
  • Fill half of your plate with veggies and fruit
  • Eat lean proteins
  • Find a good balance between eating and exercise
  • Eat calcium-rich foods

What About Milk?


Students need the calcium and other essential nutrients in milk to help their bones grow in length and density, and for healthy teeth. You should get about 3 servings a day of milk, yogurt, and cheese. Dairy is a great source of calcium, potassium, and protein. Check out these other facts on dairy.

What is a Calorie?

Vegetables and calorie counting top view

A calorie is a unit of measure, just like an inch or pound. Calories measure how much energy food gives your body. Calories also measure how much energy you use up when you are active. When you eat, your body uses food as fuel, burning it to produce energy. Your body needs energy to function.

Calories in some foods are easier for your body to use. Experts recommend you get about half of your calories from carbohydrates, about 1/5 of your calories from proteins, and fats should provide no more than 1/3 of your calories.

Food and your weight

Happy eating habits of kid

Your weight stays the same when the number of calories you take in from food equals the number of calories your body uses to maintain itself and be active. That is, if the calories you consume in a day meet your body's demands, all the calories will be converted to energy. If the number of calories are more than what your body uses and needs, the calories are stored as fat. If you eat too few calories your body may not have enough energy to fuel its cells. Then you won't have much energy and you may not be able to think clearly.

So in order to maintain a well-balanced diet, you should drink plenty of water, eat healthy portions of foods from all the food groups and have plenty of physical activity.

Why Is Physical Activity Important?

Group of children playing tug-of-war outdoors

Healthy children are both well-nourished and physically fit. Physical activity means movement of the body that uses energy. Walking, bike riding, playing tag, climbing the stairs, playing soccer, or dancing are all good examples of being active. For health benefits, physical activity should be moderate or vigorous and add up to at least 30 minutes a day. Discover more about why exercise is cool.

Exactly how does your body use food?

Your digestive system is the series of organs and glands that processes food in order to get all the nutrients from the food you eat.

It starts breaking down food even before you take your first bite and continues to work long after you've stopped eating.

Your small intestine is about 22 feet long!!

You are now an expert about nutrition and a healthy diet. Challenge yourself to eat healthy and get plenty of physical activity every day!!

Top 10 Questions

February 2013

Thanks to Ruth Schneider, Associate Professor of Nutrition, Idaho State University; and Colleen Fillmore, Director, Child Nutrition Program, Idaho State Department of Education for the answers.

  1. How does nutrition relate to a better life?

    When you eat a balanced diet, you have more energy and feel better. You are getting all of the nutrients you need. Nutrients are your carbohydrates, proteins, and fats. You are also getting your micro-nutrients which are your vitamins and minerals. By consuming a balanced diet and not just eating one kind of food, your body metabolizes food better and you have more energy. (From Addison at Riverside Elementary School in Boise)

  2. Why is water so important for your body?

    Water is one of the main essential nutrients. Your body is about 60% water. Everything that happens in your body happens in the medium of water. All of the chemical reactions take place in water. So, it's really the nutrient you can't live without. You can live quite a while without other nutrients, but you can only live a few days without water. (From Brooke at Riverside Elementary School in Boise)

  3. How much food is a serving?

    It depends on the person, their gender (male or female), and their age. Younger people can have more servings throughout the day and take in more calories. As you get older, your metabolism slows down so you need less. We recommend that you look at the USDA Choose My Plate Program and it will tell you the serving sizes that you need for your age, gender, and current weight. (From Gavin at Dalton Elementary School in Dalton Gardens)

  4. Which food group is the healthiest for you?

    Overall, the healthiest food groups that we eat are the macro-nutrients. The foods that are less processed. You would want to have a chicken breast cooked fresh versus one that is frozen or processed. Processed foods tend to have more chemicals and are higher in sodium and additives. It's healthier to eat food cooked from scratch. Otherwise, one food group is not healthier than another. You need them all to have a balanced diet. (From Afton at Riverside Elementary School in Boise)

  5. Why did they change the food pyramid to MyPlate?

    The food pyramid was hard for people to understand. We all eat off of plates, so it's easy for us to see the proportions of different foods and organize the recommendations by the plate rather than by a pyramid. They really did it to make it easier for the consumer to understand the message. (From Paige at Dalton Elementary School in Dalton Gardens)

  6. What's the most important part of the food pyramid or MyPlate?

    All parts are important because of the nutrients the food groups contain. It's important to get food from every group. There are the proteins, grains, fruits and vegetables, and some dairy. All contribute to getting a healthy diet. (From Claire at Cynthia Mann Elementary School in Boise)

  7. Can you have too much healthy food?

    You can consume too many calories whether it's from healthy food or foods that are lower in vitamins and minerals. So you want to make sure that your calorie intake is equivalent to your physical activity. It's really a mathematical equation. To maintain your weight, eat the amount of calories that your body burns. (From Emily at Dalton Elementary School in Dalton Gardens)

  8. How do calories burn energy?

    Food provides macro-nutrients, which are protein, fat, and carbohydrate. Those three nutrients provide calories which is a way we measure the energy in food. Our body has a very complicated metabolism system that takes food and breaks it down, forming ATP (Adenosine-5-triphosphate). ATP helps to transport energy for metabolism, and your body uses this energy to think, run, play, and do all sorts of different activities. It even keeps your heart beating. Eating breakfast can make you smarter by giving you the energy you need to learn all day long. (From Jack at Riverside Elementary School in Boise)

  9. How do we know if the food that we buy is safe?

    There are several regulations and laws that are put into place to keep our food safe. Whether it's the proteins, fresh produce, grains and more, they all have regulations that they have to follow. If food is determined not to be safe, it is recalled. (From Michael at Riverside Elementary School in Boise)

  10. How can your small intestine be 22 feet long when you are not even seven feet tall?

    Your intestines are very long and narrow. They wind around back and forth and kind of get stuffed into your abdominal cavity. In fact, your small intestine has the absorptive capacity of a football field. This is because in the walls of your intestines there are fingerlike projections called villi, and on those are microvilli. If you took all that surface area and spread it out, you would have a lot of surface area for all of the nutrients to be absorbed. (From Logan at Dalton Elementary School in Dalton Gardens)