Before starting a diet and during its implementation, there are always many concerns that need answers, such as if the proteins get fat. As you probably already know, foods are made up of different nutritional principles: fats, carbohydrates or sugars and proteins. In this case in particular I will refer to proteins, and whether they may or may not gain weight.
Each of the macronutrients that make up the food contribute calories to the diet: 1 gr. Of carbohydrate provides 4 kcal, 1 gr. Of fats provides 9 kcal and 1 gr. Of protein gives 4 kcal.
Although each nutritious principle contributes calories one could say that according to their function these calories are used for different metabolic processes.
Carbohydrates primarily fulfill an energetic function, lipids or fats a function of energy reserve and proteins a forming and restorative function of tissues, muscles and membranes. If you consider these functions, not all calories will be used to form fat deposits.
Therefore, the proteins are not fattening; Increase muscle mass. They provide the same amount of calories as carbohydrates, but are not used in the same way, as energy or to create an energy reserve, but to form muscles. Therefore, they are the stars of the fad diets like the Dukan diet, the Atkins diet, among others.
In fact I must tell you that not only do the proteins not fatten, but that no nutritive principle fattens; As your body needs them to stay healthy. Weight gain will depend on the amount of sugars and fats you add to your diet. Nevertheless, it is necessary to incorporate them into the diet in a balanced and harmonious way. It is best to stay lean and healthy.