The protein diet is one that bases its main calories in proteins, which are made up of amino acids few molecules. These nutrients are essential to the functioning of the cells of all living beings because tissue structure, help muscle regeneration (especially after physical exertion) and have metabolic and regulatory function. Proteins are present in every balanced diet in the form of animal protein (eggs, meat or milk) and / or vegetable (cereals, legumes, nuts ...). According to the World Health Organization (WHO) it is recommended that the percentage of vegetable protein in our diet is at least 75% of the total as they are digested better than animals and contain no fat or cholesterol. The protein diet has a dietary plan focused on the loss of body fat (not muscle fat) and improving our physical condition and our eating habits (decreasing the intake of sugars and fats). In this diet we proceed to phase out consumption of carbohydrates and fats, which are replaced by protein products of high biological value helping thus to burn the reserves of these nutrients that our body has. It is, therefore, a diet rich in protein, which needs to be controlled by a specialist because it follows a plan of gradual nutrient removal and reinstatement, also gradually, once the objectives are achieved.