What to Eat for an Upset Stomach

Reflux is when the contents of your stomach (such as acid) travel up your esophagus, which can cause heartburn. It can be caused by weakening muscles at the base of the esophagus. If reflux happens chronically, it’s called gastroesophageal reflux disease (GERD).

Symptoms: Burning, pressure, and pain in the upper abdomen, chest, or throat.

Timing: Usually within an hour or two after eating, and while lying down.

The Fix: Getting rid of reflux may be as simple as cutting out or reducing trigger foods. Your doctor may also prescribe acid-controlling medications or order imaging tests to rule out esophageal damage or a hiatal hernia, which allows food and stomach acid to back up.

Food intolerances affect about 20 percent of the population. While the symptoms can be similar to a mild allergic reaction, an intolerance—sometimes called a sensitivity—means you have a sensitivity to certain food additives or chemicals, or you’re missing enzymes needed to fully digest parts of a food (such as the lactose in dairy).

Symptoms: Gas, bloating, cramping, diarrhea, nausea, headache, joint pain, brain fog, fatigue, itching.

Timing: Within a few hours after eating.

The Fix: You can avoid triggering foods, but you may not have to eliminate them completely. Just try eating them in smaller amounts.

There are also some over-the-counter enzyme supplements that can help you digest troublesome foods, such as lactase to help you digest the lactose in dairy foods, or fructase for fructose in some fruits. Your doctor may be able to help you rule out an allergy and determine the foods causing the symptoms, but Klingbeil recommends avoiding at-home tests because they often show that you have a problem when you don’t.

Most food allergies occur earlier in life, Pimentel says, but it’s possible to develop one at any age. Changes to the gut microbiome and the intestinal lining may contribute to allergies in older adults, which are often undiagnosed, according to a 2019 review.

Symptoms: They’re similar to those for food intolerances but also include more severe reactions, some of which might be life-threatening: trouble swallowing or breathing, a swollen tongue, rapid pulse, and sudden drop in blood pressure.

Timing: In most cases, within minutes to a couple of hours after eating.

The Fix: Identifying the food and avoiding it. The most common allergies are to wheat, dairy, soy, eggs, sesame, tree nuts, peanuts, fish, and shellfish. "It’s important to get allergy testing with an allergist and keep an EpiPen on hand for severe reactions," Klingbeil says. "With food allergies, it [a reaction] can be mild one time but send you into anaphylaxis the next."

You may not have to eliminate foods you’re intolerant to completely. Eating them in small amounts may be enough.

This autoimmune condition with genetic roots is a reaction to gluten, a protein in wheat and rye. It’s becoming more common in older adults, according to the Celiac Disease Foundation, and 60 percent of such cases go undetected. Over time, gluten damages the small intestine in people with the disease. This inhibits nutrient absorption and can lead to deficiencies.

Symptoms: Abdominal pain, bloating, gas, diarrhea or constipation, fatigue, rash, migraine, achy joints, nausea.

Timing: A few hours to a few days after eating gluten.

The Fix: A doctor can do blood tests and an intestinal biopsy to check for celiac disease. But you must still be eating gluten when you’re tested. Once diagnosed, the only way to resolve symptoms and the associated risks is to avoid all foods that contain gluten, even in small amounts. Continuing to eat gluten can raise the risk of anemia, bowel cancer, osteoporosis, and more.

IBS—not to be confused with inflammatory bowel disease (IBD), which involves damage to the GI tract—is a catchall name for chronic gut problems. Generally, the diagnosis is made after other causes of digestive distress, like celiac disease, have been ruled out.

IBS has many causes. They include an overgrowth of bad bacteria in the small intestine, a compromised intestinal lining, a bout of food poisoning, and changes in gut-brain communication. "We know that stress, anxiety, and depression may have an adverse effect, too," Pimentel says. Eating certain foods—such as wheat, garlic, onion, cauliflower, fruit, milk, soft cheeses, and legumes—can also trigger IBS. That’s because they’re high in hard-to-digest carbs called FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols).

Symptoms: Abdominal pain, cramping, bloating, fullness, regularly occurring constipation or diarrhea (or both).

Timing: Symptoms sometimes come on right after eating, but they’re often more a part of daily life.

The Fix: Treatment and testing for IBS often depends on whether the primary symptoms involve constipation, diarrhea, or both, says Melissa Hershman, MD, a gastroenterologist and an assistant professor of medicine at the Oregon Health & Science University School of Medicine in Portland. Your doctor may recommend dietary changes (such as a low-FODMAP diet), cognitive behavioral therapy, or meds for specific symptoms.

When people don’t feel good after a meal, they may start cutting back on food, says Ashley Hurst, RD, a dietitian at the Houston Methodist Hospital. But "we definitely want to keep people eating," she says. Here are a few things you can do to reduce distress without sacrificing nutrition.

Eat mostly minimally processed food. Ultraprocessed foods—like hot dogs and sugary drinks—may be low in nutrients and have additives that can affect healthy gut bacteria.

Check your meds. Some common drugs, such as calcium channel blockers, cause digestive problems. Ask your doctor whether any of your meds could be responsible for your discomfort.

Chew your food slowly. This improves some symptoms, like bloating, Klingbeil says.