>>1076simply put, you need 0.5 grams to 1 gram of protein per pound of bodyweight. You need this or else your body won't have the resources to produce Glutathione (#1 anti-oxidant in the body that basically is equivalent of health)
so if you weigh 130 lbs you need to be eating at least 65 grams of protein a day.
whey protein is very healthy to do this with.