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Energy

Calories explained

PUBLISHED : Wednesday, 06 July, 2011, 12:00am
UPDATED : Wednesday, 06 July, 2011, 12:00am

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What is a calorie?

A calorie is a measure of the energy in the food you eat. We all need energy to stay alive, and we get it from food. Your body 'burns' this fuel to make the energy you need.

Why do we need calories?

Different people need different amounts of energy. Your body needs energy to breathe, pump blood, digest food, absorb nutrients and stay active. Some activities use more energy than others. The more active you are, the more energy your body uses up.

Where do calories come from?

Your body gets energy from nutrients: carbohydrates, fats and proteins. Carbohydrates and proteins provide about four calories (sometimes referred to as kilocalories) per gram, while fats provide more than twice as many: nine calories per gram.

Most foods contain a mixture of carbohydrates, protein and fat, so different foods and drinks provide different amounts of energy. Most fruits and vegetables contain few calories. Other foods, like deep-fried chicken wings or French fries, contain a lot of calories.

Carbohydrates are the most important source of energy for the body. They come from bread, rice, potatoes, pasta, beans and breakfast cereals. Proteins come from meat, eggs, fish, milk, cheese, nuts and beans. Fats come from butter, oil, pastries, ice cream, deep-fried foods, meats, cheese, pizza, nuts and mayonnaise.

What happens if we eat too many calories?

Your weight depends on balancing how much energy you consume from food and drinks against how much energy you use up by being active. When you eat or drink more energy than you use up, you put on weight; if you consume less energy from your diet than you use up, you lose weight. If you eat and drink the same amount of energy as you use up, your weight remains the same.

How many calories do we need?

Energy needs depend on a person's build, size, sex, age and exercise habits. Most teenagers need between 1,600 and 2,500 calories a day.

How to make better choices

Substitute this ...
with this
Calorie savings

1 cup whole milk
1 cup skimmed milk
60

Large hamburger
Regular hamburger
450

Super-size fries
Small fries
405

110 grams potato chips
110g air-popped popcorn
488

140g croissant with butter
140g English muffin with jam
100

55g peanuts
55g pretzels
160

140g French fries
140g baked potato
324

110g pasta with pesto
110g pasta with tomato sauce
260

2 tablespoons mayonnaise
2 tablespoons low-calorie dressing
104

1 chocolate chip cookie
2 dried figs
111

2 scoops ice cream
2 scoops frozen yogurt
100

10 deep-fried chicken wings
10 grilled chicken skewers or chicken satay
513

1 chocolate brownie
1 ginger snap biscuit
198

55g luncheon meat
55g lean ham
118

Take the QUIZ

Test your calorie IQ

1 Which has fewest calories?

a. 100g sticky rice wrapped in lotus leaf

b. 100g baked barbecue pork puff

c. 100g steamed barbecue pork bun

d. 100g pan-fried turnip cake

2 Which activity would be the best to help you burn off calories?

a. 1 hour of tennis

b. 1 hour jumping rope

c. 1 hour walking hills

3 How many calories does a 340g can of cola contain?

a. 50 calories

b. 95 calories

c. 155 calories

d. 350 calories

4 How many calories are there in a sausage bread?

a. 100 calories

b. 200 calories

c. 300 calories

d. 400 calories

5 Which of the following contains the most calories?

a. 100g congee with preserved egg and pork

b. 100g instant noodles with luncheon meat and egg

c. 100g fried rice noodles (ho fun) with beef

d. 100g fried rice with pork and tomato

6 How many minutes of fast swimming is needed to burn off the calories from one pineapple bun?

a. 5 minutes

b. 15 minutes

c. 30 minutes

d. 60 minutes

Answers:

1. b (barbecue pork puff contains 440 calories, turnip cake 130 calories, sticky rice 210 calories, barbecue pork bun 260 calories)

2. b (jumping rope burns 572 calories, walking hills burns 324 calories, singles tennis burns 464 calories)

3. c (155 calories)

4. c (a 90g serving of sausage bread contains around 300 calories)

5. d (fried rice contains 180 calories, instant noodles 140 calories, congee 52 calories, fried rice noodles 160 calories)