# The difference between cals and kcals



## ci1 (30 Jan 2008)

Have been trying to find this out on the net but none of the explanations are clear to me.

I'm basiclly trying to find out if 100g of a certain food equals 100kcals then how to I work out the amount of cals or are they the same?

thanks,


----------



## ClubMan (30 Jan 2008)

Surely a kcal is 1000 cals?


----------



## ci1 (30 Jan 2008)

So if something is 1 kcal its actually 1000 cals??


----------



## ClubMan (30 Jan 2008)

ci1 said:


> So if something is 1 kcal its actually 1000 cals??


Hang on a minute - let me see....

Yep - that's exactly what I and _Wikipedia _said.


ClubMan said:


> Surely a kcal is 1000 cals?


----------



## redstar (30 Jan 2008)

Seems to depend on the type of food.
100g of fatty food yields more kcal energy than 100g of Carbs

Energy per gram: Carbohydrate - 4 kcal, Fats - 9 kcal and Protein - 4 kcal.
So
100g of cake = 100 x 4 = 400kcal
100g of butter = 100 x 9 = 900kcal
100g of eggs = 100 x 4 = 400kcal

See      http://www.brianmac.co.uk/nutrit.htm

kcal here means kilocalories, not thousand-calories. The kilo refers to the 1000g of water in the definition below ...



> A calorie (cal) is the amount of heat energy required to raise the temperature of 1g of water 1°C from 14° to 15°C. A kilocalorie (kcal) is the amount of heat required to raise the temperature of 1000g of water 1°C.



So, 1 cal = 1kcal.


----------



## z103 (30 Jan 2008)

You would think that was is the case, but in everyday use, cal = kcal


----------



## ci1 (30 Jan 2008)

thanks for your helpful reply Redstar.


----------



## z103 (30 Jan 2008)

Just looking at this again.



> A calorie (cal) is the amount of heat energy required to raise the temperature of 1g of water 1°C from 14° to 15°C. A kilocalorie (kcal) is the amount of heat required to raise the temperature of 1000g of water 1°C.


So to clarify, 1000 cal = 1kcal is correct
However, when people talk about calories, they really mean kcals.
So, in everyday talk, 1cal = 1kcal.


----------



## ajapale (30 Jan 2008)

from [broken link removed]

I think the key is the concept of the *Large Calorie* and the *small calorie*.

Peronally I would use the standard SI unit Joules or kJoules.


ENERGY 

Just as there are many forms of energy, there are different ways to measure these forms. In science, work and energy are commonly measured in joules. One joule is the amount of energy it takes to lift an object that weighs one Newton a one meter distance. A Newton is the metric unit for weight and is comparable to the weight of a stick of butter. (1 Newton = 0.445 lbs.)

In our everyday lives, other energy measurements are more familiar to us than joules. Some of these measurements include calories, therms, and kilowatt-hours. Definitions of these and other units are found below. 

It might seem confusing to have so many different measurements for energy. The good news is that one unit can be converted to another.

Definitions: 

*British thermal unit - (abbrev. Btu)* 
1. A unit of energy equal to 1,055 joules or 252 calories. 2. The amount of energy needed to raise the temperature of one pound of water one degree Fahrenheit. 3. The approximate amount of energy in one match tip. 

*calorie (abbrev. cal; pl. calories; also small calorie):* 1. A unit of energy often used when measuring the energy content of food. One calorie equals 4.187 joules or 0.003969 British thermal units (Btu). 2. The amount of energy needed to raise the temperature of one gram of water one degree Celsius.  

*Food calorie (abbrev. Cal, kcal; also Calorie [written with a capital C], Kilocalorie, Large calorie)*: A unit of energy equal to one kilocalorie. The food calorie is often used when measuring the energy content of food.  

*Joule* - A unit of energy. One joule equals 0.2388 calories or 0.0009481 Btu. 

*Kilocalorie (abbrev. Cal, kcal; also Calorie [written with a capital C], Food calorie, Large calorie):* 1. A unit of energy equal to 1000 calories, 4,187 joules, or 3.969 Btu. 2. The amount of energy needed to raise the temperature of one kilogram of water one degree Celsius.  Kilowatt-hour (abbrev. kWh; pl. Kilowatt-hours): 1. A unit of energy equal to 3,413 Btu or 3,600,000 joules. 2. An amount of energy that results from the steady production or consumption of one kilowatt of power for a period of one hour.


*Therm - (pl. Therms)* A unit describing the energy contained in natural gas. One therm equals 100,000 Btu. See British Thermal Unit.


----------

