We are always hearing about calories. We say cut your calories and you lose weight or if you want to gain weight add calories to your diet. Well, I bet you’d like to know just what a calorie is.

A calorie is not an object that you can touch. It’s actually a unit of heat or measure of heat. Let me explain it this way. All foods are composed of some combination of carbohydrates, fats, proteins, vitamins and minerals, fiber, water or some amount of micronutrients. When you put food into your body and I do mean through the hole that is your mouth it becomes one of four things: part of your body such as muscles ,skin, bones, guts etc., Body fat, waste products, or heat.

Now, your specific body mass or body weight, whatever it is, requires a certain number of calories to maintain that mass or weight. Let’s say for example it’s 2000 cal per day. If you take the total calories consumed in a day and it is more than 2000 cal you will store the extra calories in the form of body fat.
Conversely, if you consume less than 2000 cal in a day (let’s say 1800) your body will take 200 from its storage (body fat) and you will lose weight.

Here’s the tricky part. We are talking about the total calories in a day, including all fat, carbohydrates, and protein. Fats and carbohydrates are used almost exclusively for energy. Protein on the other hand is used for multiple purposes including maintaining structures and transport of nutrients and even though it’s primary purpose is not energy it can be used as energy and certain situations, therefore it is included in the calorie total for the day.

What your body actually does is convert the carbohydrates or fat you have eaten either into body fat or actual heat that radiates from your body into the atmosphere and is recycled.