MEASURING ENERGY
We can measure energy in different ways. The energy provided by a food or a
drink is usually measured in kilojoules, but we talk about calories.
1 calorie = 4.2kJ
(kilojoules)
The amount of energy your body needs depends on your age, gender, size,
health and how active you are. But you can use around 50 calories every hour
just for basic processes like breathing, growing and pumping blood around the
body.
The more active you are, the more energy or calories you will use up. Have a
look at this table. Which activity uses the most energy? Which uses the least
energy?
Energy used by a 10 year-old for daily activities
| Activity |
Average calories used per minute |
Average calories used per hour |
| Sleeping |
0.8 |
48 |
| Sitting |
0.9 |
54 |
| Helping with housework |
1.7 |
102 |
| Dancing |
4.2 |
252 |
| Walking |
1.9 |
114 |
| Cycling |
3.1 |
186 |
| Swimming |
4.2 |
252 |
| Running |
5.5 |
330 |
How many calories do we need?
On average, boys aged 7 to 10 need around 1970 calories every day. Girls aged
7 to 10 need about 1740 calories every day. But this is only a guide – if you're
very energetic and always on the go, you may need more than this. If you're less
active, you may need fewer calories.
How many calories are in food?
Food and drink provide the calories your body needs. Here are some examples
of the calories in some everyday foods. They are only average amounts and will
depend on the size of the portion. You can check the labels on different foods
to see how many calories they contain. But remember that the type of food you
eat is important too, to give you all the nutrients you need. You can find out
more about this in the Food for life
section.
| Food |
Average energy content (calories) |
Food |
Average energy content (calories) |
| 1 banana |
80 |
1 apple, 1 orange or a handful of grapes |
50 |
| porridge with milk |
55 |
stir fried tofu with vegetables and rice |
300 |
| 200ml of semi-skimmed milk |
92 |
macaroni cheese |
380 |
| 1 can fizzy cola |
135 |
chicken curry with vegetables |
350 |
| 1 glass of orange juice |
50 |
vegetable soup |
120 |
| 1 small cereal bar |
100 |
dried fruit (raisins) |
120 |
| 1 pot of low fat yogurt |
100 |
cheese and pickle sandwich |
280 |
| 1 slice of toast with butter |
100 |
egg mayonnaise sandwich |
320 |
| 1 fun-sized chocolate bar |
100 |
vegetables and rice |
320 |
| 1 small packet of crisps |
150 |
vegetables and noodles |
320 |
| 1 small chocolate bar |
150 |
roast chicken, vegetables and potatoes |
420 |
| 1 slice chocolate cake |
230 |
lamb chops, vegetables and potatoes |
450 |
| 1 blueberry muffin |
200 |
roast beef, vegetables and potatoes |
420 |
| crackers and cheese |
200 |
baked beans on toast (2 slices) |
300 |
| breakfast cereal with semi-skimmed milk |
200 |
mixed raw vegetable salad (lettuce, tomato,cucumber etc.) |
120 |
| wholemeal pitta bread and houmus |
200 |
1 flapjack |
100 |
| ham and cheese sandwich |
250 |
2 jaffa cakes |
90 |
| baked potato |
190 |
1 plain biscuit |
50 |
| baked potato with cheese and beans |
300 |
1 pot of creamy yogurt |
180 |
| baked potato with chilli |
280 |
fruit with custard, ice cream or cream |
220 |
| baked potato with coleslaw |
280 |
trifle |
220 |
| 1 slice of quiche |
390 |
pancakes with ice cream |
220 |
| 1 sausage roll |
400 |
swiss roll |
130 |
| potato chips |
350 |
fruit jelly |
100 |
| cheeseburger |
400 |
mixed nuts |
150 |
| stir-fried chicken with vegetables and rice |
300 |
popcorn (plain) |
120 |
| vegetarian pizza with salad |
450 |
pasta with tomato-based sauce (e.g. bolognese) |
350 |
| fish, vegetables and potatoes |
450 |
meat samosa |
175 |
| pasta with vegetables and salad |
350 |
vegetable samosa |
160 |
| chicken chop suey with rice |
450 |
steak and kidney pie |
330 |
| 1 chapatti |
110 |
chicken casserole and dumplings |
380 |
| scrambled egg |
147 |
shepherds pie |
380 |
| omelette |
191 |
fish pie |
400 |
| cheese omelette |
266 |
moussaka |
460 |
| fried eggs |
179 |
naan bread |
150 |
| 2 slices of toast with spread |
225 |
croissant |
280 |
