It’s 2 a.m. and my phone wakes me up with a start. My patient, Christine Z*, is vomiting uncontrollably, and Dr Google has diagnosed her with acute pancreatitis from semaglutide (Wegovy). Ten hours, several imaging studies, one blood draw, and many bags of fluids later, the verdict is in: Christine is alarmingly constipated. In fact, her entire large intestine is packed to the brim with stool. In residency, we called this diagnosis FOS, and I’ll leave it to your imagination to figure out what it stands for.
In retrospect, Christine mentions that upon raising her Wegovy dose, her bowel movements had become increasingly smaller and infrequent. This begs the question:
Proper nutrition always starts with drinking copious amounts of water. In general, I recommend a minimum of 64 ounces of water daily in patients taking incretins such as semaglutide (Wegovy for weight loss, Ozempic and Rybelsus for type 2 diabetes) or tirzepatide (Zepbound for weight loss, Mounjaro for type 2 diabetes). While these medications don’t directly dehydrate patients, they can increase the risk for dehydration due to severe nausea. Drinking copious amounts of water can prevent dehydration, preserve kidney function, and minimize fatigue and dizziness. In addition, fluids help soften bowel movements, making them easier to pass.
Occasionally incretins make it so easy for patients to drop pounds that their eating patterns become sloppier — more sweets and simple carbohydrates. I recommend a realistic and low glycemic index meal plan. While no foods are strictly contraindicated, processed, high-sugar, and fatty foods are likely to worsen side effects like nausea and gastrointestinal distress. Similarly, alcohol not only worsens nausea, but it’s also likely to exacerbate reflux by relaxing the sphincter that separates the stomach from the esophagus.
The next most important dietary advice is consuming sufficient fiber. In the majority of patients, increasing fiber intake relieves constipation. There are two types of fiber: soluble and insoluble. In practical terms, most fiber-rich foods contain a mixture of these two types. The general recommendation is 38 g/d for men and 25 g/d for women. The caveat to this advice is that a minority of patients, such as those with irritable bowel syndrome, may develop worsening constipation with increasing fiber.
To minimize side effects, some patients find it useful to eat five small meals throughout the day rather than three larger meals. In addition, I recommend eating slowly and stopping before the point of satiety. Finally, because weight loss of any kind is inevitably associated with muscle loss, I stress the importance of adequate protein. In general, I advise 25-30 g of protein per meal.
Christine eventually restarted her Wegovy after recovering from her grueling night in the emergency room. As this was her second go-around on Wegovy, she dug out my “guide to preventing side effects of incretins” and followed it to a T. So far, she’s feeling great.
*The patient’s name has been changed.
A version of this article appeared on Medscape.com.