Nowadays we use the word “diet” mainly when we mean that someone is trying to lose weight. “I am on a diet” usually means that a person doesn’t eat high-calorie food. This word has become so popular that it is often used as a marketing tool. For example, in a supermarket we can find dietary biscuits, dietary dairy products and even dietary Cola. But does the prefix “dietary” make all these products really good for our health? Of course, no. “Dietary” is not a synonym for “healthy”, as well as “diet” is not a synonym for “healthy nutrition”. In fact, a diet is just a way of nutrition, or a sum of all food products that are consumed by a particular person. A diet can be healthy or unhealthy, vegetarian, milk-free or zero-carb; it can be intended for losing or for gaining weight, and so on. The diet, which is good for one person, can be absolutely unacceptable for another one.