What Are Calories?

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The term “calorie” is nothing more than the unit of measurement of the amount of heat; more precisely, it is the quantity of heat necessary to raise 1 gram of water by 1 degree centigrade. From a dietary-nutritional point of view, kilocalories consist of the energy that food and drinks provide to the body to meet energy needs.

The energy requirement represents the amount of calories that a subject must guarantee daily to promote the metabolic activities defined as basal, and to be able to carry out daily physical activity.

The energy requirement, in turn, depends on three factors

  • Basal metabolism represents the calories required by the body, in conditions of rest, to maintain vital physiological functions (blood circulation, nervous function, respiration, glandular and metabolic activity, and maintenance of body temperature);
  • Diet-induced thermogenesis, or the energy expended to digest and absorb food;
    Physical activity, or the energy required to carry out daily activities such as walking, washing, dressing, etc.

From these simple definitions it is understandable how that of calories is a system that, on its own, cannot explain or summarize the complex metabolic and biochemical mechanisms that take place in our body, which is why it is not so easy to lose weight just by counting calories.

breakdown of calories in a diet

Composition of Calorie Consumption

Diet is not just a matter of counting the calories to be removed, on the contrary, the success of a diet depends a lot on elements such as the quality, variety, nutritional value of the foods that are brought to the table.

In addition, the calorie intake in a diet must also be divided according to macronutrients such as: carbohydrates, proteins and fats.

In fact, a calorie from a slice of meat is different from that of a slice of bread or a teaspoon of oil, because their assimilation and the body’s need for certain nutritional elements are different. Sticking to the mere caloric calculation, carbohydrates and proteins provide 4 kcal per gram, fats instead 9 kcal per gram.

  • Composition of Calorie ConsumptionBased on these values, applying the aforementioned model for the caloric deficit (- food + energy expenditure = weight loss), we would tend to consider a prevalent consumption of carbohydrates in the diet, limiting the intake of fats.
  • In fact, according to classic dietetics, about 60% of the total Kcal that a person should guarantee for the sustenance of the body should come from carbohydrates. Going beyond this approach, and considering other aspects such as the quality and the effects that macronutrients have on our cellular metabolism, we must abandon the calorie count.

This numerical calculation, in fact, in itself says very little about the potential effects of a food on our health. A slice of pizza or a bowl of chicken salad could also have the same calories, but the second option provides more useful nutrients that at the same time do not excessively alter post-prandial glycemic homeostasis.