One food group that can be hard to digest is dairy — mainly because of the sugar lactose found in milk and other dairy products. When lactose isn’t digested properly, such as in people with lactose intolerance, gas and bloating result. If you consume too much lactose, it goes into the large intestine, and diarrhea can develop or worsen. During digestive problems, it may still be okay to eat yogurt and hard cheeses because they have no lactose, or you can try lactose-free milk.
If you’re experiencing nausea, vomiting, and diarrhea, you’ll want to avoid food choices that stimulate the digestive system, and these include spicy foods, says Jung Kim, a registered dietitian and specialist with Clinical Nutritional Support Services at the Hospital of the University of Pennsylvania in Philadelphia. Spicy foods are “incredibly variable,” says Dr. Krevsky — they have no effect on some people, but cause indigestion for others. In general, you should choose bland foods when you’re having digestive problems, and be sure to avoid spices if you’re sensitive to them.
Tomato sauce and citrus fruits, such as lemons, limes, oranges, and grapefruits, are acidic and can cause digestive problems. Many people don’t realize that carbonated beverages are also acidic — Krevsky says that if you leave a pearl in a glass of soda pop overnight, it will dissolve. When you have an upset stomach, avoid acidic foods, he says.
Fatty foods stimulate contractions in the digestive tract, which, surprisingly, can either slow down the emptying of the stomach and worsen constipation or speed up movement and worsen or lead to diarrhea. The effect can depend on the type of fat and your tendency toward constipation or diarrhea. When you’re experiencing a bout of indigestion, put low-fat foods on the menu and eat small meals spaced throughout the day, which can put less pressure on your stomach. Avoid high-fat culprits, like butter, ice cream, red meat, and cheese, at least for a while.
The problem with fried foods is the same as with fatty foods — they can move, undigested, through the body too quickly, leading to diarrhea, or stay in your digestive tract too long, causing you to feel full and bloated. Many fried foods are low in fiber and take longer to digest. So if you’re dealing with either diarrhea or constipation, you’ll want to avoid fried foods for a while. The conventional wisdom, says Krevsky, is that when you have indigestion, you should avoid fried foods because they tend to slow down the emptying of the stomach.
Caffeine stimulates gastrointestinal tract motility, making contents move more quickly through your system, and excessive amounts can give anyone diarrhea, Krevsky says. So if you already have diarrhea, caffeine will only worsen your digestive problem. He also warns against simply switching to decaf coffee because it still has some caffeine. Remember that tea, soda, and chocolate are other sources of caffeine, and should be put on hold until tummy troubles go away.