After having weight loss surgery, the body will not be able to absorb, use, or take in enough nutrients from diet alone, to maintain good health unless supplements are utilized.  For this reason, it is strongly urged that all post-op patients take daily vitamin supplements with iron, extra calcium, and vitamin B-12 to prevent nutritional deficiencies and related medical conditions, such as hair loss, skin problems, nausea, food intolerance, or more severe cases of malnutrition.