A lack of protein can cause someone to develop edema. Edema is a condition that is characterized by swollen and puffy skin, most commonly in a person’s extremities (like the feet or ankles). The reason for these skin issues is fluid retention. When an individual does not get enough protein in their diets, fluid can seep into surrounding tissues and salt and water are not properly held in blood vessels. The key indicator that someone is suffering from edema is if a finger is pressed on the area the shape of the fingerprint is present even after several seconds.