What is a calorie?

There's been talk in the news lately about requiring restaurants to list the caloric content of foods on the menu to help consumers make wise meal choices. Without some coaching, however, in our age of information overload it may be confusing to understand what it all means other than the fact that eating "a lot" of them is "not good".

Thermodynamically, a calorie is actually known as a "kilocalorie" and is the amount of energy required to raise the temperature of 1 gram of water by 1°C from a standard initial temperature.

In layman's terms, the calorie is referred to as the way scientists express how much energy is produced by food, specifically the macronutrients: carbohydrate, protein, and fat.

The energy breakdown is as follows:

Carbohydrate - 4 calories per gram
Protein - 4 calories per gram
Fat - 9 calories per gram

Calories are the currency of movement. Physiologically, no movement can occur without them. As long as you live, your body uses calories every moment of every day whether you're sleeping or awake, running or lying still.

How? Basal metabolism.

Your basal metabolic rate (BMR) refers to the minimal amount of energy necessary to maintain respiration, circulation, and other vital body functions while fasting and at total rest. As you may have guessed by now, this includes breathing, breaking down food, and keeping your heart and brain working. BMR is directly effected by your age, gender, weight, and physical activity.

Fortunately, there are things that you can do to increase your BMR, and therefore the number of calories you burn, even while doing "nothing".

Next time: how many calories do you need?

wildfire on instagram