1. Chew the fat-4

2. A calorie is a unit of measurement — but it doesn't measure weight or length. A calorie is a unit of energy. When you hear something contains 100 calories, it's a way of describing how much energy your body could get from eating or drinking it.
Calories aren't bad for you. Your body needs calories for energy. But eating too many calories — and not burning enough of them off through activity — can lead to weight gain.
You can find out show many calories are in a food by looking at the nutrition facts label. The label also will describe the components of the food — how many grams of carbohydrate, protein, and fat it contains.
Here's how many calories are in 1 gram of each:
carbohydrate — 4 calories protein — 4 calories fat — 9 calories
For example, if a serving of potato chips (about 20 chips) has 10 grams of fat, 90 calories are from fat. That's 10 grams x 9 calories per gram.
each person's body burns energy (calories) at different rates, but the recommended range for most school-age kids: 1,600 to 2,200 calories per day.
When you eat more calories than your body needs, the leftover calories are converted to fat. Too much fat can lead to health problems.
So avoid high-calorie foods, such as sugary sodas, candy, and fast food, and by eating a healthy, balanced diet. 
Exercising and playing are really important, too, because activity burns calories.

3. Everybody needs foods that include:
As a kid, your body also needs calories from a variety of foods to grow and develop. And you burn off some calories without even thinking about it — by walking your dog or making your bed.
But it is a great idea to play and be active for at least 1 hour and up to several hours a day. That means time spent playing sports, just running around outside, or riding your bike. It all adds up. Being active every day keeps your body strong and can help you maintain a healthy weight.
Watching TV and playing video games won't burn many calories at all, which is why you should try to limit those activities to 1 to 2 hours per day. A person burns only about 1 calorie per minute while watching TV, about the same as sleeping!
Everybody needs foods that include:
protein (found in meat, poultry, seafood, eggs, beans, nuts, and dairy foods)
carbohydrates (fruits, vegetables, and whole grains are the best sources)
vitamins -found in fruits and vegetables and minerals like calcium (found in dairy products)
Fat - found in meats, cheeses, nuts, oils, and butter etc

4. Calcium and iron are two important nutrients for kids
Calcium builds strong bones, its found in dairy products, like milk, yogurt, and cheese. Other good sources include dark, green leafy vegetables and calcium-fortified products, like orange juice.
It's important to include iron-rich foods in your diet, such as meat, dried beans, and fortified cereals. Without enough iron, kids might get tired more easily.
When people sweat, they lose water through their skin. Sweating cools the body down, but if you lose too much water this way, you could get dehydrated and you won't feel well and can make you sick enough that you'd need to go to the emergency department for treatment.
Drinking water is the best way to stay hydrated. Don't wait until you're thirsty. Water is the best choice. Fruit juice mixed with water is another refreshing drink. But avoid sodas.
Water does not have any calories and its very healthy to drink water.

5. Metabolism  is a collection of chemical reactions that takes place in the body's cells. Metabolism converts the fuel in the food we eat into the energy needed to power everything we do, from moving to thinking to growing.
First, a green plant takes in energy from sunlight. The plant uses this energy and a molecule called chlorophyll (which gives plants their green color) to build sugars from water and carbon dioxide. This process is called photosynthesis
When people and animals eat the plants (or, if they're carnivores, they eat animals that have eaten the plants), they take in this energy (in the form of sugar), along with other vital cell-building chemicals. Then, the body breaks the sugar down so that the energy released can be distributed to, and used as fuel by, the body's cells.
Simply put, metabolism influences how easily our bodies gain/lose weight
A calorie is a unit that measures how much energy a particular food provides to the body.
A chocolate bar has more calories than an apple, so it provides the body with more energy —the body stores calories — primarily as fat. If a person eats too many calories, they "spill over" in the form of excess fat on the body.
The number of calories someone burns in a day is affected by how much that person exercises, the amount of fat and muscle in his or her body, and the person's basal metabolic rate (BMR). 
BMR is the rate at which the body "burns" energy, in the form of calories, while at rest. BMR can play a role in a person's tendency to gain weight. For example, someone with a low BMR (who burns fewer calories while at rest or sleeping) will tend to gain more pounds of body fat over time compared with a similar-sized person with an average BMR who eats the same amount of food and gets the same amount of exercise.

6. REFERENCES http://kidshealth.org/en/teens/metabolism.html
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