Jordan Robison has what many Americans would consider a “good” problem: She struggles to gain weight. Whether smearing peanut butter on her apples or dunking her broccoli in cheese, someone’s bound to tell her she’s lucky she’s so small. She sees it differently. “People are so jealous that I can eat whatever I want and not gain weight,” says the 23-year-old dietetic intern in Lubbock, Texas. “To me, that’s so frustrating … because it’s like, ‘Well you probably don’t want what I have.'”

What she has is exocrine pancreatic insufficiency, or EPI, a condition in which the pancreas doesn’t produce enough digestive enzymes to adequately absorb the nutrients in food. As a result, people with EPI can experience common digestive woes — think gas, bloating and diarrhea — as well as more serious medical complications including weight loss, vitamin deficiencies, osteoporosis and diabetes. If left untreated, people with EPI could theoretically die from malnutrition.

“It’s fascinating — the spectrum of consequences from EPI,” says Dr. Christopher Forsmark, chief of the University of Florida Division of Gastroenterology, Hepatology and Nutrition. “Some [patients] come in very malnourished,” and others appear healthy, he says.

For Robison, who was diagnosed with cystic fibrosis and EPI as a baby, life with the condition is all she’s ever known. But if she doesn’t follow her treatment regimen diligently, she quickly discovers what it would be like to live with undiagnosed EPI: “I have a lot of GI issues,” she says, such as bloating, gas and more frequent bowel movements that are particularly smelly. “There’s a lot of not fun stuff that comes with EPI if you don’t do what you’re supposed to do.”

A Difficult Diagnosis

Gas, bloating, diarrhea, stomach aches — who hasn’t been there? That mentality — plus feeling squeamish about toilet talk — can cause patients to brush off EPI symptoms and doctors to misdiagnose it, says Dr. Roshini Raj, a gastroenterologist in New York City and medical host on “Good Day NY.” “People say, ‘I’ve been having diarrhea and bloating and pain for years and it’s like … ‘You didn’t have to live like that for so long,'” she says.

[See: How Often Should I Poop, and Other Toilet Topics.]

A lack of good, simple diagnostic tests for EPI only makes it more difficult to identify, says Forsmark, who is on the American Gastroenterological Association’s Institute Council. “One of the biggest challenges we have is just making a diagnosis of EPI because there’s no easy way to do it,” he says.

For instance, one of the more thorough ways of diagnosing EPI — by analyzing three days’ worth of stool for its fat content — is also among the more impractical. “As you can imagine, keeping poop around the house for three days is not good for anyone,” says Dr. A. Jay Freeman, an assistant professor of pediatrics in Emory University School of Medicine’s Division of Pediatric Gastroenterology, Hepatology and Nutrition.

Most clinicians, then, rely on a test that measures the amount of a certain pancreatic enzyme in stool. “It’s very good at picking up moderate to severe EPI,” Freeman says, “but it’s a little less reliable if you have mild to moderate.” Other diagnostic tests, which involve inserting a tube into the small intestine, have “gone the way of the dinosaur,” Forsmark says.

Often, patients are diagnosed with EPI because the condition goes hand-in-hand with others, namely cystic fibrosis and chronic pancreatitis, an inflammatory disease that can result from genetic mutations, smoking and alcohol abuse. “There’s this perception on the part of many doctors that if you have chronic pancreatitis, you’re an alcoholic,” a stigma that can make patients “dread” visits to nonspecialists, Forsmark says. People who have had pancreatic surgery can have EPI, too, since the procedure may block ducts that secrete enzymes.

Ultimately, it’s up to patients to talk bluntly to their doctors about gastrointestinal issues of any kind, since an accurate EPI diagnosis also relies on a detailed history of the types and timing of symptoms, Raj says. For instance, people with EPI often have fatty stools that float and experience their GI symptoms after eating — and particularly after eating high-fat foods, she says.

[See: Foods That Cause Bloating.]

Being frank about such details with your doctor is worth the discomfort. Once people are diagnosed, Raj says, “It’s [a] relief that there is an identifiable cause to what’s going on and there’s a plan to trying to treat it.”

Life With EPI

The people who think Robison’s stubbornly small figure is a gift don’t know that she and other people with EPI must carry enzyme pills everywhere and eat them with every meal and snack — or suffer the uncomfortable consequences. “You learn really fast if you’re not perfect at it,” she says. “It’s also important to know that it’s OK to make mistakes; you just have to learn from those.”

While these supplemental enzymes — which come from a pig’s pancreas — are the main treatment for EPI, they leave room not only for user error, but also for prescriber error, since doctors widely underdose enzymes and often wrongly instruct patients to take them before they eat, rather than while they eat, Forsmark says. In recent years, generic brands have stopped making enzymes, which can also leave patients unable to pay for the up to $1,000-per-month pills, Forsmark adds. “Cost is much more of an issue now,” he says.

Diet and physical activity are also important parts of managing EPI, experts say. While patients like Robison with both cystic fibrosis and EPI are told to eat about 1.5 times more calories than other people their size, since cystic fibrosis patients in particular burn more calories just keeping their bodies functioning, people with just EPI also typically need to eat a higher-calorie diet since their bodies might not absorb all of the nutrients in food. But no longer does that mean eating everything and anything. For cystic fibrosis patients, Freeman says, “we’ve gone from a calories-at-all-cost recipe to trying to improve overall nutrition.”

[See: The 10 Best Diets for Healthy Eating.]

Robison, for one, finds ways to add healthy, high-calorie foods like nuts and cheese to her diet. “It’s important to include a variety of foods from all the food groups,” she says. Fueling her life like that has paid off: She recently got married — a big deal for someone who was told she might not live long enough to say “I do” — works a 40-hour week, studies for her master’s degree, plays with her dog and hangs out with friends. “I’m still able to be who I want to be with EPI,” she says.

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EPI: The Serious But Little-Known Cause of Digestive Issues originally appeared on usnews.com