5 types of foods to avoid while taking a GLP-1

The idea of there being an “GLP-1 foods to avoid” list sounds a whole lot like diet culture, where you have to banish all of your favorite foods. But there’s a valid reason for having this kind of guideline when taking a GLP-1: Some foods can trigger unpleasant side effects, like nausea, or make it hard to get all the nutrients you need on a reduced appetite. So, while there’s no official GLP-1 eating plan, reducing how much you consume of the below foods can be a good idea.

Fried foods, full-fat dairy, and anything greasy can be difficult to digest — it’s why people often feel some sort of gastrointestinal discomfort, such as bloating, nausea, abdominal pain, and diarrhea after eating a high-fat meal on these medications. One of the ways GLP-1s work is by slowing down gastric emptying, which means food stays in your stomach longer and you feel full for an extended length of time. When you consume fatty foods, which can already put a strain on your GI tract, they linger longer in your system, making those uncomfortable symptoms worse.

Learn more about GLP-1 side effects

Sweetened beverages — the biggest source of added sugar in the American diet — and other sugary foods can cause rapid spikes in blood sugar levels while offering little nutritional benefit. While GLP-1s do help lower your blood sugar, doctors recommend that you still keep an eye on your intake of added sugar.

That’s because if you’re on one, your insulin levels are higher than if you weren’t on the medication, explains Dr. Pouya Shafipour, M.D., a board-certified physician specializing in family and obesity medicine in Santa Monica, California. (One mechanism of GLP-1s is stimulating insulin production.) When you consume something high in sugar, like candy or soda, your insulin levels go even higher in response. This extra-high insulin level could trigger a sharp crash in blood sugar levels, leading to symptoms such as fatigue, irritability, difficulty concentrating, dizziness, anxiety, nausea, and shakiness.

Refined carbs such as white bread, pasta, rice, pastries, sugary cereals, and other processed foods have a higher glycemic index than whole grains and, like high-sugar foods, can spike your blood sugar levels. They also don’t offer much in terms of nutrition, and anyone taking a GLP-1 should make an extra effort to prioritize nutrient-dense foods, says Caroline Susie, R.D., a Dallas, Texas-based registered dietitian and spokesperson for the Academy of Nutrition and Dietetics. This is because the medication reduces your appetite and makes you full faster, so you need to ensure you’re getting all the vitamins, fiber, and protein you need.
Learn more about the best GLP-1 diet

This isn’t true for everyone, but if you experience acid reflux or heartburn after eating something spicy, those side effects may be exacerbated while on a GLP-1. “Anything that can cause acid reflux — be it spicy food, garlic, or onion — tends to be more dramatic [when you’re on the medication],” says Shafipour. Since spicy food stays in your stomach longer on a GLP-1, it can intensify these side effects, which may also include nausea.
Learn more about how to manage acid reflux while on a GLP-1

There's no hard rule saying you can’t enjoy a glass of wine when on a GLP-1, but it’s important to keep in mind that alcohol may not always sit well in your stomach. Alcohol is already known to cause GI distress, such as upset stomach, diarrhea, and acid reflux, so you may feel even worse when it’s combined with the medication (which can also cause those things). Thus, it wasn’t surprising that when Weight Watchers did a study looking at changes in alcohol consumption in patients on GLP-1 medications, almost half cut down on alcohol consumption.