Dairy is hard to digest because of lactose, the sugar found in milk and other dairy products. If you consume too much lactose, it goes into the large intestine, and diarrhoea can develop or worsen.
Tomato sauce and citrus fruits, such as lemons, limes, oranges, and grapefruit, are acidic and can irritate the stomach lining, causing digestive problems. Many people don’t realise that carbonated beverages are also acidic. When you have an upset stomach, avoid acidic foods.
Fatty foods stimulate contractions in the digestive tract, which can either slow down the emptying of the stomach and worsen constipation, or speed up movement and lead to worsening diarrhea.
The problem with fried foods is the same as with fatty foods — they can move, undigested, through the body too quickly, leading to diarrhoea, or stay in your digestive tract too long, causing you to feel full and bloated.
If you’re constipated, you should avoid processed foods because they lack fibre, which helps regulate bowel movements. Note that some packaged foods also contain lactose, which can give you gas and worsen any discomfort you’re already going through.
Alcohol is toxic to the stomach lining and changes liver metabolism. Drinking too much can cause indigestion, among other health problems.
Caffeine stimulates gastrointestinal tract motility, making contents move more quickly through your system, and excessive amounts can give anyone diarrhoea. So, if you already have diarrhoea, caffeine will only worsen your digestive problem.