What Actually Is A Calorie?

We hear a lot about calories but what exactly is a calorie?

‘A calorie is a unit to measure heat.’ It is the amount of energy needed to raise the temperature of 1 gram of water by 1 degree.

As you know I like to calorie count but it is not 100% accurate. Errors occur that are out of our control.

Calories can be measured in two ways:

1) Bomb calorimeter (measures calories in food)

2) Direct calorimeter (measures calories in humans)

Bomb calorimeter
Bomb calorimeter is a small oven-like box submerged in water. Food is placed in the oven and is electrified. While the food is burning up the heat of the water is increased and recorded.

This is not the most accurate test though for 2 reasons:

1) The human body doesn’t perform as consistently as the bomb calorimeter for a number of reasons. We could burn these calories slower or faster depending on our state i.e. Netflix and chill vs heavy resistance training.

2) Food companies are responsible for reporting how these foods perform. They report each individual component, and this is where the problem occurs – they don’t measure the calories directly but instead estimate them. All these small errors (estimates) can lead to bigger ones in total calories of the product.

Direct calorimeter
This testing involves a human inside the calorimeter rather than a food product (this calorimeter is about the size of a bedroom). The person could be in it from a few hours to a few days. The amount of heat produced from the body is measured directly.

This style of testing helps to create data which scientists use to formulate the average heat produced of a particular age, gender etc. while performing a particular test i.e. running, sleeping.

An issue with this though is that your metabolic rate could be different from the outside world compared to when you are in the calorimeter. This could be due to feeling anxious, nervous or tired, to name a few variables, which would effect results.

This is a very geeky post but it’s good to know what an actual calorie is and how foods get their calorie contents.