The cells and all cellular structures are made mainly of proteins, in a way the cell is not only a protein container filled with water, and nutrients are dissolved in the liquid, so we need to form new structures of proteins. That is, we are made of protein, that is the stuff that shapes us. We need daily one gram of protein per kilogram of body weight (500 mg / pound). A man needs a woman 70 grams on average 60g. Proteins are composed of amino acids that are 22, nine are considered essential because the body lacks the ability to form or synthesized, by force should get with our food.We need proteins containing all essential and nonessential amino acids in a balanced way. If either is missing from the diet or are in insufficient quantities, causes the body can not form all the proteins we need every day.It is recommended that 40 of the protein we eat is of animal origin and 60 of plant origin. Proteins in food shortage for many reasons: Undernourishment. Lacking in our food proteins. Diets to lose weight. When someone wants to lose weight, stop eating usually 10 to 20 days, in those days he can only drink coffee, water or juice.The body needs protein every day to survive, and because the body there is a place for storage, starts taking the proteins needed for their own muscles, ie “eat” your muscles. As a result, the diet a person loses fat and muscle, fat 5 kilos (10 lbs) of muscle and 1 kilo (2 lbs). This program provides enough protein so that when you lose weight, lose only fat and no muscle.