Protein-energy can be classified into:Secondary PEM is caused by disorders in the gastrointestinal tract. It is also caused by infections, trauma, and much more.Primary PEM includes kwashiorkor and marasmus which are highly prevalent in children in rural areas of Africa and other developing nations in the world. This leads to weakening of the immunity of the person which leads to them being highly susceptible to diseases, illnesses, and ailments. These are the two classifications of protein energy malnutrition.