If you develop constant diarrhea after eating, you may be suffering from a few different conditions. If the constant diarrhea developed suddenly, you could have viral gastroenteritis or food poisoning. If you notice diarrhea after eating certain foods, you may have an allergy to certain proteins found in various foods. If you notice that you develop diarrhea every time you eat, you may have a more serious condition, such as irritable bowel syndrome or celiac disease.
One of the primary symptoms of viral gastroenteritis, sometimes called the "stomach flu," is diarrhea. If you have the stomach flu, you won’t be able to keep any food in your system. You will develop symptoms such as nausea, vomiting, stomach cramps, chills, abdominal pain and diarrhea, according to MedlinePlus. Eating can cause episodes of vomiting and diarrhea. The stomach flu is a viral infection that lasts for one to three days and is highly contagious. If you have the stomach flu, implement a bland and simple diet while you still have symptoms. Avoid eating large meals and foods that are spicy, high in fat or highly processed.
Food poisoning occurs when you eat or drink something that is contaminated. Within a few hours or up to one day, you will begin to feel sick to your stomach. Every time you eat something, you will experience diarrhea. Diarrhea from food poisoning can last for up to two weeks after the initial episode. Food poisoning is commonly caused by a lack of proper hand washing, food handling and eating leftovers. The PubMed Health website states that symptoms may include cramping, fever, chills, headache, vomiting and weakness.
Food allergies can cause constant diarrhea after eating. MayoClinic.com states that 90 percent of all food allergies are caused by seven foods: fish, shellfish, nuts, soy, eggs, milk and wheat. A food allergy causes inflammation to develop in your small intestines, which causes nausea, vomiting, diarrhea, stomach pain and vomiting. Food allergies will cause other symptoms to develop, such as skin rashes, nasal congestion and asthma.
Two other common chronic conditions that can cause consistent diarrhea after eating are irritable bowel syndrome, or IBS, and celiac disease. With IBS, the nerves and muscles in your bowel may be ultra sensitive; muscles may contract too much when you eat, causing cramping and diarrhea shortly after eating; or your nerves may react when your bowel stretches, causing cramps. Celiac disease is a condition where gluten, a protein found in wheat, causes damage to your intestines, resulting in constant diarrhea.