Calories and Kilojoules

IndigoElectron

Most of you will probably know this already, but I read in one post recently that someone was confused about how many kilojoules are in one calorie (I think their HRM counted in kJ and they needed to convert it).

Anyway - there are 4.2 kJ in one calorie.

IndigoElectron

Most of you will probably know this already, but I read in one post recently that someone was confused about how many kilojoules are in one calorie (I think their HRM counted in kJ and they needed to convert it).

Anyway - there are 4.2 kJ in one calorie.

shorerider

Kilojoules are used in many countries outside the U.S. as a measurement standard instead of the Calorie, and 1 Calorie equals 4.184 kilojoules.

HOWEVER--The person was asking about KCals, which some, including mine, HRM read. They're different than Kiljoules. A KCal is the same as a Calorie, in so far as 1 KCal = 1 Calorie, in the sense that we here in the States use the term. I read that scientifically they are different but as we use them in daily language now, they mean the same.

For example, if you eat something that contains 100 calories, then exercise and burn up 100 KCals, you've burnt up the calories from that 100 calorie item, in other words.

Here's a great explanation I found on the 'net----

Question: What is the corrolation between KCalories as presented on my heart rate monitor and calories figures found on a purchased grocery item? Can one be converted to the other?


That is a great question, and something that I bet many people have wondered. A kilocalorie and a "Calorie" as you see it listed on a food label are one and the same. So, if you are using a heart rate monitor and it reads that you have burned 250 kilocalories while working out, that would be the same as buring the 250 Calories you consumed from drinking a 16 ounce bottle of regular soda.



Calorie is a measure of energy and we need energy to do everything, including breath, get up and move around, and move blood through our body. The number of Calories in a food item represents the potential amount of energy that food item has. One Calorie from fat has the same amount of energy as one Calorie from protein or one Calorie from carbohydrate.


If you look closely at a food label, you will notice that the word "Calorie" is probably spelled with a capital C, this is usually the case when referring to the calorie content of food because 1 food Calorie is equal to 1 kilocalorie. Now, if you go back to your middle school math you'll remember that 1 kilo of something actually means 1000, so 1 kilocalorie is actually equal to 1000 calories or units of energy. One calorie with a lower case c, is the measure of how much energy it takes to raise the temperature of 1 gram of water 1 degree Celsius.

But I don't want to confuse you - so the take home message is that kilocalorie and Calories listed on a food label are the same.

IndigoElectron

Ah I see. What made me think of it was looking at a recipe site, where the energy content was given in kJ, so I had to find out how many were in 1 calorie and convert it.

shorerider

See my edited post above--sorry, I just edited my original post instead of posting again but you were too quick!