Читать книгу Nutrition For Dummies - Carol Ann Rinzler - Страница 65

IN THIS CHAPTER

Counting the calories in different nutrients

Explaining why women need fewer calories than men

Setting realistic calorie requirements for your own body

Automobiles burn gasoline to get the energy they need to move. Your body burns (metabolizes) food to produce energy in the form of heat that keeps you warm and (as energy) powers your every move and thought.

The amount of heat produced by metabolizing food is measured in a unit called the kilocalorie — the amount of energy it takes to raise the temperature of 1 kilogram of water 1 degree on a Centigrade (Celsius) thermometer at sea level.

For the non-chemists in the room, 1 kilogram = 1 liter = 1/4 U.S. gallon. As for temperature, 1 degree on the Celsius thermometer = 33.8 degrees on a Fahrenheit thermometer. To convert any temperature from Celsius to Fahrenheit or vice versa, use the following equations, which illustrate a 0 degree temperature, the simplest example:

 °F = °C × 9/5 + 32

 32°F = 0°C × 9/5 = 0 + 32 = 32°F°C = (°F – 32) × 5/9

 0°C = (32°F – 32) = 0 × 5/9 = 0°C

Nutritionists commonly substitute the word calorie for kilocalorie. Strictly speaking, a true calorie is just 1/1,000 of a kilocalorie, but the word calorie is easier to say and easier to remember, so that’s what you see when you read about the energy in food.