Understanding Calories

As we venture into the mechanics of energy balance, you’re going to see the word ‘calorie’ a lot, so I’ll briefly explain it now.

A calorie is a unit that represents the amount of energy that is needed to heat one gram of water by one degree celsius. Nothing more, nothing less.

What we know as a calorie when talking in terms of nutrition is actually a kilocalorie which is one thousand ‘little calories’ so our big calories heat up a kilogram instead of a gram. This is why it says ‘kcal’ on food labels but for now when referring to nutrition a calorie and a kilocalorie are the same thing. I couldn’t tell you why, it’s just the way it is.

A calorie is just a unit of energy, that’s all. It can be easy to forget this, we read the health magazines and diet books that tell us that we don’t need to count calories or that it’s unhealthy to ‘obsess’ over calories, so it’s understandable that people get confused.

A calorie is a unit of energy just as a millimetre is a unit of length. You wouldn’t fit a kitchen unit without a tape measure and you don’t need to obsess over millimetres to cut a piece of wood. In fact, one trait of those who are successful in long-term weight loss and maintenance is consistent measuring of body weight and food intake.

To lose weight you must burn more calories than you consume, this is the basis of weight loss. You can not lose weight reliably without monitoring your food intake.

One of the reasons that calorie counting is so important is that most people overestimate or underestimate their food intake – by a lot. We all know a thin person who claims they eat a lot and an overweight person who claims they barely eat. Most people quite dramatically overestimate how many calories they burn too.

In the next section we’ll cover how to calculate your calorie needs and how to measure calories in food.