When it comes to nutrition, people often use calories to evaluate a food or diet. In fact, calories have become the most frequently used tool for any type of assessment - to determine how much to eat, when choosing foods, and for planning recipes and meals.
In the last few decades, calories and fat (as they are calorie-rich foods) have been the focus of attention because they are believed to be responsible for the increase in weight of “industrialised” populations that are affected by this issue. In spite of that, this approach has not solved the problem which has, if anything, continued to grow. It is therefore wise to consider this problem in a different light and understand that calories are not the best way to assess food.
The body is not just a machine (to which it is often superficially compared), but rather a metabolic mechanism that actively responds to food intake.
Let's consider carbohydrates and protein. From a caloric point of view, they are the same because they each have a value of 4.1 calories per gram. But the hormonal response that they induce is quite the opposite. Carbohydrates stimulate the production of insulin, while protein acts on glucagon, the hormone that transforms nutrients into energy. Not taking this into account may lead to incorrect conclusions about the cause of weight increase. This doesn't mean that one should only eat protein to lose weight - that assumption would be incorrect. It does, however, mean that calories are not the only parameter needed to fully assess a correct diet.