Upset stomach is a problem many people have, but not enough people discuss. Approximately 25 to 45 million Americans suffer from irritable bowel syndrome and roughly 65 percent of the population has at least some trouble digesting lactose after infancy. Even fructose intolerance—an often unrecognized or misdiagnosed condition—is on the rise.

Why do more and more people seem to be suffering from digestive issues? There’s not one answer, says Lori Chong, RD, dietician at The Ohio State University Wexner Medical Center in Columbus, Ohio, but it may have to do with the gut’s microbiome, or its mix of good and bad microorganisms. “Studies show that healthier people have a more diverse microbiome,” she says, “whereas that same diversity is lacking in most people with chronic disease.”

Unfortunately some of your gut development is out of your control. “Babies delivered by C-section aren’t exposed to the same microbes in the vaginal canal that eventually take up residence in the child’s GI tract,” says Chong. “These microbes benefit the maturing immune system and promote good diversity in the GI flora. Breastfeeding also promotes the proliferation of good gut bacteria.”

The good news? What you eat now can still make a big impact. “Whole, plant foods produce a GI microbiome that is diverse and beneficial,” says Chong. “Eating only a few foods, or eating too much sugar and not enough fiber, promotes a less diverse microbiome.” Other issues that can play a role in developing a finicky gut? Foodborne infections, stress, and anxiety.

If you’re having recurring gastrointestinal symptoms, like diarrhea and constipation, it’s wise to get checked out by a doctor—don’t wait if you’re having symptoms that may be a sign of something more serious, like fever, weight loss, blood stools, anemia, or pain that wakes you up in the night. Until you’re armed with an official diagnosis, try to find immediate relief by making some dietary changes.

To start working towards a happy gut, Chong recommends keeping a food diary, paying particular attention to the foods below, which research shows tend to cause the most tummy troubles. These culprits often fall in the high-FODMAP camp.

Foods high in lactose: Think cow’s milk, yogurt, ice cream, or soft cheeses.

Foods high in fructose: Think any food with added sugars or high-fructose corn syrup, or high-fructose fruits like apples, pears, cherries, and mangoes.

Foods high in certain oligosaccharides: Think onions, garlic, wheat, artichokes, lentils and chickpeas.

Foods high in sugar alcohols: Think low-carb treats, sugar-free ice creams, breath mints, and sugar-free gum.

To start identifying your triggers, note the food and beverages you consume, along with the amounts of each. “Also record the symptoms you’re concerned about as they occur,” says Chong. “For example, if your main symptom is bloating, then record when that occurs, how severe it is, and how long it lasts.”

If you eat a lot of foods in one category, start there: Cut back on them to see if your GI woes begin to clear up. If those changes don’t have an impact, you can re-integrate what you cut out, moving onto a new set of potentially troublesome foods. One food category or multiple categories may be impacting your stomach, so continue with your diary until you’ve seemed to locate all potentially problematic foods. (A gastroenterologist or RD can help you if you’re struggling to locate all your triggers.)

And if you have a particularly rich, layered meal and wind up with an upset stomach, gas, bloating and general discomfort? There’s not one easy way to reverse the damage, but you can sometimes find a little relief, says Chong: “I like a digestive tea [available from multiple brands], or ginger tea.” Sip it after eating to quell gas and bloating or before bed to rest easier. “You could also try a sequence of yoga poses known to stimulate bowel motility,” she says.