Why is feces black during weight loss

During weight loss, black stool may be related to dietary adjustments or gastrointestinal bleeding. Common reasons include consuming iron containing foods, taking iron supplements, consuming dark colored foods, and in rare cases, being alert to upper gastrointestinal bleeding. During weight loss, if animal liver, blood products, or high iron foods such as spinach are added, the iron element may cause the stool to turn black after digestion. Some weight loss patients taking iron containing nutritional supplements, such as ferrous sulfate tablets, ferrous fumarate granules, etc., can also cause black stool. When consuming large amounts of dark colored foods such as mulberries and black sesame seeds, the incompletely absorbed pigments may cause feces to appear black. These conditions are physiological changes, usually without discomfort such as abdominal pain, and the color can return to normal within 2-3 days after adjusting the diet. When black stool is tar like and accompanied by a fishy odor, the possibility of upper gastrointestinal bleeding should be considered. Excessive dieting during weight loss may cause stress-induced gastric mucosal damage, and long-term use of nonsteroidal anti-inflammatory drugs may also lead to gastric bleeding. After bleeding from diseases such as gastric ulcers and duodenal ulcers, the blood decomposes in the intestine to produce ferrous sulfide, resulting in characteristic black stools in the stool. This type of situation is often accompanied by anemia symptoms such as dizziness and palpitations, and immediate medical attention is needed for gastroscopy or fecal occult blood test. During weight loss, it is important to maintain a balanced diet and avoid extreme dieting. The sudden appearance of black should be recorded in the diet list to observe whether it is related to specific foods. If it lasts for more than 2 days or is accompanied by symptoms such as abdominal pain and vomiting blood, it is necessary to seek medical attention from a gastroenterologist in a timely manner. Daily intake of fiber rich foods such as oats and apples can help maintain normal intestinal peristalsis. It is recommended for those taking iron supplements to adjust the dosage under the guidance of a doctor, and if necessary, to supplement with vitamin C to promote iron absorption.