In the middle of all the diet confusion comes a question that can seem self-explanatory but in reality is not always so, at least not for everyone. It’s about the difference between two common concepts: energy and nourishment. Understanding the difference is absolutely fundamental to nutrition and to learn how to get in shape, or shape up. It is common that these concepts are confused and used incorrectly; therefore, it seems like a good idea to begin with these as a basis for understanding.
The body needs and is dependent on both energy and nourishment.
Energy, when it comes to food and drink, is usually measured in kJ (kilojoules) or kcal (kilocalories)—colloquially speaking, “calories”—which actually is a simplification of kilocalories.
The body gets energy in the form of calories from what we eat and drink through so-called energy-rich nutrients: protein, carbohydrates and fat. The body even gets energy from a fourth substance, alcohol, which you know is something the body doesn’t need.
Moreover, there are also nutrients that do not yield energy—vitamins, minerals and antioxidants—that the body needs in addition to the energy-rich substances. Because these nutrients provide nourishment without giving energy, they have other functions in the body; therefore, it is important that we consume all of these substances.
Clarification: Protein, carbohydrates and fat (and alcohol) are nutrients that produce energy when they are broken down in the body. Vitamins, minerals and antioxidants, however, are nutrients that do not provide energy but have other important functions in the body.