The answer is Anemia—iron-deficient diet. Anemia is a result due to the lack of iron which caused the decrease of the number of red blood cells in the body. If you do not have enough iron then it will result to fewer and smaller red blood cells in your body. As we all know, hemoglobin is used to carry oxygen, so when you lack hemoglobin,there is a lack of oxygen supplying for your body also.