How do you calculate Calories?

Question

By which I mean, how does a scientist/food manufacturer actually work out using what ever equipment is needed how many calories there are in some food?

And what do calories measure?

Excellent answers both, thank you. But why then are calories a measure of how much we should have on our intake? Or is it an easy reference which covers fat and sugar, etc

Answer 1

Calories are a measure of heat content. One device for measuring calories in food is a device called a bomb calorimeter; it is a sealable chamber, containing an igniter, in which a food sample can be placed along with oxygen under pressure. The sample is ignited, and the temperature rise measured. On a food package, if you know the number of grams of sugars, starches [collectively, carbohydrates], and fats, you can multiply the carbs by 4.2 and the fats by 9.1 to get the calorie content.

Answer 2

You could lose a stone by just exercising and it looks like that's what you have planned anyway. You can also cut down on sugary foods and eat more leafy greens and lean protein. Processed foods aren't really healthy, so ham could be replaced with lean chicken breast meat and watch the sugar content of tinned soup - you'll be surprised how much they contain. You're better off making your own or buying the chilled ones. Why just an egg white omelette? A whole egg only has about 80 calories, depending how it's cooked. You don't seem to be eating enough calories to be honest. As you have a year to lose the weight, you can do this really sensibly.

Answer 3

The info on calories and finding the calories in food is correct. Heat =mass x specific heat of the material x temperature change. The calories in food actually are Kilo calories, or 1000calories, sometimes written as Calories. The Calories you need are dependent on your size and activity. Follow the food pyramid and make serving size about the size of 1/2 cup. Calories measure heat or energy.

Answer 4

this is the answer to your second question :
Calories is a unit to measure heat which is a form of energy
The human body requires a particular amount of energy to function. Hence they use calories to define the sugar/ fat intake
Also, a bomb calorie meter is used to measure the calories in a food substance.

Answer 5

Food is burned in a machine called a bomb calorimeter. The amount of heat energy released is how many calories that food has. A half teaspoon of sugar is burned in an instant, and releases 2 joules of heat energy. Therefor a half teaspoon of sugar has 2 calories.

Answer 6

1 calorie is the amount of heat require to raise 1 cc of water 1 degree (celcius)

Answer 7

Heat, boiling, incinerating.
Like the other person said.