How are calories worked out?

I don't know, but that is a very interesting question!

firfenwen wrote: »

I'm pretty sure I read somewhere that the food is burned and the resulting heat and light energy is recorded as a measure of calories.

Yes that's how they do it. Kcal can vary quite a bit and even prepackaged products can be 10% out either way due to natural variances e.g. One portion of chicken or veg could have more water content than another. If you are trying to lose weight just log everything and it balances out. If a generic item try and find a realistic value i.e. A giant cake is not going to be 100kcals so don't choose this just because it is in the database, find the most realistic.

trigden1991 wrote: »

timeforwork wrote: »

Just wondering how the amount of calories per piece of food is worked out? I don't mean this in a diet related way but more like a mad scientist in a lab experimenting type thing! Anyone know as Google tends to try to send you to calorie counting pages and I got fed up seeing debates about how many calories per egg ( must be a very common search!) thanks all in advance x

They use a bomb calorimeter which basically burns the food to allow them to calculate the energy output.

What he said. We learned about it in biology in high school. It was always I weird to me that someone thought of it. Like hey lets burn some food and see if it can affect out weigh loss or gain. Lol.