Gastroparesis: Is Your GLP-1 Slowing Digestion Too Much?

Gastroenterologists must sort through the roughly 10 digestive symptoms a person can experience to untangle the root cause from among thousands of conditions of the GI tract.

Indigestion, bloat, stomach cramps and aches, or even regurgitation after a sip of soda, are often lumped together as vague tummy troubles or more common, widely known illnesses such as irritable bowel syndrome (IBS). Increasingly, though—with the rise of medications slowing digestion and growing recognition of the problem—the diagnosis is gastroparesis.  

Researchers estimate in Gastroenterology that the painful illness affects nearly 267 in 100,000 adults, according to an analysis of medical claims, a vast leap from the approximately 22 in 100,000 formally diagnosed. A further 1 in 4 people experience its characteristic symptoms, according to the National Institute of Diabetes and Digestive and Kidney Diseases.

“Sometimes people just brush off their symptoms and think, ‘Let’s move on,’ but for all gut disorders—even IBS—treatment has advanced dramatically,” said Ali Rezaie, MD, medical director of the Cedars-Sinai Gastrointestinal (GI) Motility Program.

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Food Paths to Digestion

Every bite we eat travels through the esophagus into the stomach, where it’s broken down by acids and stomach muscles and then winds its way into the small intestine. In a healthy person, the stomach should purge the bulk of the food in about four hours. In gastroparesis, the process can take days.

“Essentially, emptying is dysregulated and delayed. If food is sitting in your stomach for eight hours, that is clearly abnormal,” Rezaie emphasized.

When digestion moves at a snail’s pace, mealtimes can feel particularly daunting. Eating very small amounts of food, even half-portions, causes extreme fullness, bloating and discomfort, and patients often have frequent stomach aches untraceable to a specific ingredient. The chronic condition can also trigger unpredictable bouts of vomiting and nausea, acid reflux and indigestion.

“Our stomach emptying rate for everyone can vary slightly day to day but may have higher variability when you have gastroparesis,” explained Cedars-Sinai digestive diseases dietitian Stephanie Mendez, RDN, CSDH.

Sometimes people just brush off their symptoms and think, 'Let’s move on,' but for all gut disorders—even IBS—treatment has advanced dramatically.

Alongside these symptoms, patients can have other gastrointestinal conditions exacerbating or overlapping with chronic abdominal pain and bloating. Nearly half (41%) of gastroparesis patients simultaneously have small intestine bacterial overgrowth (SIBO), which is believed to be fueled by food’s slow passage through the gut. After tiny particles of food reach the small intestine, nutrients are absorbed, but the long wait may nurture excessive bacteria as it ferments sugars into gases, disrupting the gut’s delicate ecosystem.

Methane gas, in particular, is linked to a more sluggish intestinal route, Cedars-Sinai investigators discovered in a groundbreaking study.

A wide range of infections also induce gastroparesis. For example, infectious gastroenteritis, which can be caused by viruses or bacteria such as E. coli or salmonella, changes the microbiome’s immune pathways. This damages nerves that are responsible for gut motility.

Heart and lung transplants or other surgeries can similarly damage nerves, especially the pivotal vagus nerve.

Diabetes, traditionally a common culprit of gastroparesis, is fortunately becoming rarer as society has made significant strides in blood sugar control. Revolutionary GLP-1 medications like semaglutide, which treat both diabetes and obesity, have helped to propel this massive sea change, but they may be counterproductive for gastroparesis patients.

A GLP-1 Gambit: Can Semaglutide Cause Gastroparesis?

“GLP-1s definitely slow down the stomach,” Rezaie explained, “and, in fact, that’s how they work.”

These popular metabolic health injections can take up to a month to leave the body. Rezaie stressed that a single dose is enough to cause long-lasting, potentially disruptive GI side effects, particularly if you are already prone to delayed gastric emptying. Be cautious and consider your individual risk factors when deciding whether or not to take these medicines.

Gastroenterologists do not typically recommend GLP-1s to gastroparesis patients.

If you are on semaglutide or tirzepatide and experience new, unexplained symptoms such as heartburn or vomiting, let your gastroenterologist or primary care doctor know right away—even if they did not prescribe the medication. Your physician can adjust the dosage, determine whether you might tolerate another, newer-generation GLP-1 (which tend to carry fewer GI side effects), or stop the treatment.

GLP-1s and other peptide therapies should always be taken under close medical supervision and care.

“Patients taking GLP-1s might be happy when they’re losing weight, but sometimes, that weight loss comes from muscle mass loss, which can harm your health,” Mendez said. “Even if you’re not hungry, I strongly recommend prioritizing consistent meals in order to get sufficient protein and nutrient-dense foods while taking these medications.”

Vigilance for Serious Malnutrition Risks

Gastroparesis interferes with our ability to digest food, among the body’s most vital functions, and if untreated, cuts off access to essential nutrients.

Some people with the condition may become deficient in iron, zinc, calcium, magnesium and folate, as well as vitamins A, D, E and K. These fat-soluble vitamins are often not as readily absorbed, because they need fat to do so. However, fat is often avoided in this group, as it’s harder for them to tolerate. Fiber can also be hard on the gut.

Patients taking GLP-1s might be happy when they’re losing weight, but sometimes, that weight loss comes from muscle mass loss, which can harm your health.

Watch for unexplained weight loss, as well as thinning hair and new fatigue, which can signal malnutrition, a potentially life-threatening concern. Rashes, sores or other unusual skin or eyesight changes can also sometimes point to hidden nutrient deficiencies, while other gastroparesis patients can show no symptoms, yet be depleted in potent vitamins and minerals.

Adults require roughly 2,000 to 2,500 calories every day for energy, including plenty of fruits, vegetables, healthy fats and protein sources. GI dietitians encourage small, frequent meals to ensure you keep up with your daily caloric needs without overwhelming your stomach.

“There’s a higher chance of food being retained in your stomach when you have gastroparesis,” Mendez said.

Consistency is key: While it’s tempting to avoid meals altogether, she stressed that malnourishment further slows digestion and may worsen discomfort. This can prevent you from eating enough, creating a “vicious cycle.”

Try stacking up the most nutrient-dense ingredients earlier in the day, eating more food in general on days when you’re feeling better, and sitting up after eating, so gravity can work in your favor.

The secret ingredient? Mendez says to choose liquids or softer foods instead of solids whenever possible—“predigesting” food by steaming, stewing, slow-cooking, pureeing or mashing it aids in digestion.

Soft alternatives help even starchy, rougher foods go down more smoothly, for example, with a butternut squash or split pea soup. Consider nut butters instead of nuts, a drizzle of oil rather than avocado, or a jar of applesauce or baby food. Mendez also recommends nutrition shakes to supplement core minerals and vitamins.

“Finding ways to get whole foods, including some soluble-fiber fruits and vegetables in a texture-modified form, is where the golden area really is,” she suggests.

Is My Stomach Pain Gastroparesis, IBS or Something Else?

Experts emphasize that persistent stomachaches or heartburn after eating, or any unintended weight loss, warrant a thorough work-up.

“Unless you seek medical help, you don’t know which GI condition you have,” said Rezaie, nor in turn, exactly how to tailor your treatment.

Cedars-Sinai gastroenterologists conduct a comprehensive medical evaluation and high-resolution imaging, including endoscopy, to detect urgent physical obstacles along the GI tract, such as tumors, stomach ulcers or inflammatory bowel conditions including Crohn’s disease and ulcerative colitis. They also test for bacterial infections and IBS—exams pioneered at the medical center—and investigate whether the gut and each of its compartments are properly sealed to prevent leakage.

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Gastric emptying studies use imaging or a breath test to assess the speed at which your body metabolizes a standardized meal or motility capsule.

Few healthcare centers offer the gold-standard exam, a major barrier in gastroparesis.

Rezaie, who also oversees bioinformatics and biotechnology in Cedars-Sinai’s Medically Associated Science and Technology (MAST) program, is developing innovative diagnostic tools and therapies for gut microbiome conditions.

“We need more awareness to push this field forward and help patients and providers be able to diagnose this disease,” he said.

Gastroparesis Care and Comfort

Gastroparesis treatment targets the GI distress that is most interfering in your life. A plethora of new medicines has come onto the scene in recent years, providing newfound relief to the 60 to 70 million Americans living with a chronic digestive disorder.

Your gastroenterologist might prescribe a combination of:

• Anti-nausea medications such as ondansetron
• Motility drugs, including metoclopramide, azithromycin and prucalopride, which bolster gut contractions to encourage regular bowel movements
• Antibiotics to combat any bacterial infections
• Diabetes treatments, if you are struggling to rein in blood sugar

Botox injections directly to the pylorus, the tube-like tunnel filtering food from the stomach to the small intestine, also support smoother passage, while specialized minimally invasive surgical procedures (G-POEM) widen the opening. In severe nausea cases that don’t improve with medication, surgeons may implant an electrical pacemaker that stimulates the stomach.

Every gastroparesis treatment plan should contain a heavy helping of nutrition support, balancing the gut and putting it at ease. Work with a dietitian, who can catch extreme weight loss and other medical emergencies. Some severe nutrient deficiencies may require tube-feeding.

Dietitians mix in your favorite comfort foods—the 20 or so ingredients each person usually rotates between—even ice cream, so your meals taste like home.