Calorie is a unit that does not belong to the International System of Units. Its function is to express the thermal energy, indicating the amount of heat that is needed, with normal pressure, to increase the temperature of 1 gram of H2O by 1ºC (from 14.5 to 15.5 ° C).
In the International System, Cal should be replaced by July (one calorie equals 4.1855 joules), although its use and retains that has become popular to express power energy possessing food.
It is possible to differentiate between two specific classes of calories: the calorie-gram (also known as the small calorie) is that heat energy that is necessary to raise the temperature of 1 gram of H2O by 1º Celsius; the calorie-kilogram (or large calorie), on the other hand, is the heat energy required for the temperature of 1 kilogram of H20 to increase by 1 ° Celsius. This distinction, however, has fallen into disuse in recent years.
Importance of calories
The notion of calorie is important to explain the functioning of the food process. Living beings need energy to survive; This energy is obtained from food. Food, therefore, is the most relevant source of energy for living organisms.
The energy obtained from the nutrients found in food is converted into calories or, more precisely, into kilocalories (that is, thousands of calories). The body uses calories in diseases, stress situations and metabolic processes.
The obsession with calories
According to DigoPaul, the number of calories present in a food must be specified on its label. This amount is responsible for informing what the energy value of the food is and is very important both to maintain the ideal weight and figure, and to try to recover them. When preparing a dish, it is essential to know how to differentiate between the different types of ingredients, use the right proportion of each one and choose the best cooking mode.
Regardless of weight problems, many people have developed a kind of obsession with the calorie content of food. The main reason is that at present there is access to a lot of information about the effects of food on health, as well as its relationship with certain chronic non-communicable diseases, among which are diabetes, hypertension and cardiovascular disorders.
Understanding the nutritional properties of food is essential to steer our diet in a healthy direction and to make this become a lifestyle and not just a passing practice. To understand each of the values indicated on packages, jars and wrappers it is highly advisable to ask a nutritionist for help.
Many times, due to lack of information and tools to understand the energy value of foods, they are misjudged and more calories are ingested than expected. A clear example is avoiding eating a chocolate cookie and replacing it with twenty cereals.
It is very important to know the distribution of the so-called macro nutrients in each food and the amount of calories per gram they provide: carbohydrates and proteins, 4; fats, 9; and alcohol, 7. To facilitate the comparison of the caloric content of various products, it is always calculated based on 100 grams of the food in question.
The more water a food contains, the less energy it provides; in the case of vegetables, for example, almost 95% of their weight is wet. On the contrary, products such as bread and nuts have a high energy value, given the small proportion of liquid present in their composition. Fats, on the other hand, are the nutrients that add the most calories; This is the case of oils, butter and margarine, among others.