Glucagon-like peptide-1 (GLP-1) receptor agonists have changed the landscape of obesity treatment, delivering significant weight loss results and improving the control of type 2 diabetes. In recent years, research is uncovering additional beneficial effects of GLP-1 receptor agonists, like improving non-alcoholic fatty liver disease, reducing cardiovascular disease risk, lowering the risk of obesity-associated cancers, and potentially preventing dementia, among others.
However, GLP-1 receptor agonists are known to cause a number of potential side effects, with gastrointestinal side effects being the most common. The good news is, in many cases, side effects like nausea, vomiting, constipation, and diarrhea can be effectively managed with diet and lifestyle strategies.
Understanding GLP-1 Medications and Nausea
What are GLP-1 receptor agonists?
GLP-1 receptor agonists work by increasing the effects of a GLP-1, which is a neuroendocrine hormone released in the intestines in response to food intake. GLP-1 is anorexigenic, meaning it promotes weight loss. It accomplishes 4 main functions:
- GLP-1 stimulates the pancreas to release more insulin, which helps reduce blood glucose by directing it to organs and tissues to be used for energy
- GLP-1 inhibits glucagon release and the release of glucose from the liver
- GLP-1 slows gastric emptying, keeping food in the stomach longer, and helping to sustain fullness over time. This lowers appetite and leads to a reduced overall calorie intake.
- GLP-1 feeds back to the brain to “turn off” appetite stimulation in the hypothalamus.
The most commonly prescribed GLP-1 medications are semaglutide (Ozempic®, Rybelsus®, and Wegovy®, liraglutide (Victoza® and Saxenda®), and dulaglutide (Trulicity®).
Why Do GLP-1s Cause Nausea?
Because GLP-1 receptor agonists slow gastric emptying, this leads to food remaining in the stomach longer, which can lead to nausea, gastroesophageal reflux, and even vomiting. Moreover, this limits the volume of food and drinks patients who are taking GLP-1 receptor agonists can tolerate, as there is simply less room in the stomach. Nausea is also a function of decreased appetite stimulation in the brain, deterring the desire to consume additional food.
Similarly, GLP-1 receptor agonists often increase the intestinal transit time, which can promote abdominal pain, gas, and bloating. Dehydration is a common factor in constipation that is related to GLP-1 receptor agonist use. The decreased appetite, stomach discomfort that results from eating or drinking larger volumes, and the potential nausea or vomiting can lead some people to not only eat less food but also drink less liquid.
General Dietary Tips to Reduce Nausea
Eat Smaller, Frequent Meals
With less room in the stomach, eating smaller, more frequent meals scan help promote easier digestion, reduce the risk of nausea and vomiting, and allow room for adequate hydration. If you are following intermittent fasting or time restricted feeding techniques in addition to taking a GLP-1 receptor agonist for weight loss, it is imperative to consume nutrient-dense foods to avoid any nutrient deficiencies. While it is important to take in adequate amounts of lean protein, it is also important to eat a rainbow of vegetables to promote good vitamin and mineral intakes. In some cases, a multi vitamin supplement may be necessary, so discuss this with your physician.
Stay Hydrated
Because the delayed gastric emptying causes the stomach to hold smaller volumes, this can predispose to dehydration. If oral fluid intake is insufficient, this means less fluid in the stool. Plus, because it takes longer for stool to move through the colon while taking GLP-1receptor agonists, more water is reabsorbed in the intestines, resulting in harder stools and thus, constipation.
The presence of nausea can also promote dehydration, as the desire to consume oral food or fluid is decreased. On the other hand, nausea can also be caused by dehydration, creating a nausea-dehydration-constipation cycle. Dehydration can be problematic not only by increasing the risk of constipation but also by increasing the risks of low blood pressure, decreased kidney function, fatigue, and weakness.
In order to stay hydrated while taking GLP-1 receptor agonists, focus on drinking small amounts throughout the day. Keep a portable bottle of water accessible throughout the day, so that it is readily available to encourage consistent water intake. Add lemon, lime, or other fruit for more flavor. While water is the best source of hydration, other drinks like green tea, unsweetened seltzers, and herbal teas are good alternatives. Foods with high water contents, like fruits and vegetables, also help promote good hydration.
Foods to Eat
Easily Digestible Foods
BecauseGLP-1 receptor agonists may cause nausea, vomiting, abdominal pain, and changes in bowel habits, many patients find that focusing on easily digestible foods lessens many of these symptoms. For example, raw vegetables are much more difficult to digest than cooked vegetables, so they are often a better choice. Other gas-producing foods (such as beans and cruciferous vegetables) may exacerbate gastrointestinal side effects while taking GLP-1 receptor agonists.
High-Protein Foods
Protein is crucial to our overall health, and it plays a key role in weight loss too. Because protein helps promote fullness, pairing adequate protein intake with the increased satiety from GLP-1 receptor agonists helps promote decreased overall calorie intake, leading to weight loss. In addition, protein has a higher thermic effect of food than the other macronutrients (carbohydrates and fat). This means that the metabolism of protein requires more energy, burning more calories in its digestion. Lastly, adequate protein intake helps build and maintain lean muscle mass, which not only improves exercise capacity but also improves resting metabolism, leading to more calories burned at rest to improve weight loss results.
Foods to Avoid
High-Sugar and High-Carbohydrate Foods
Another benefit of GLP-1 receptor agonists is decreased cravings for high-sugar and high-carbohydrate foods. These foods are known to promote weight gain and higher blood sugar, so reducing the intake of these foods is key in supporting overall health and wellbeing. However, these foods are palatable, so eating high-sugar or high carbohydrate foods often leads to a reward response in the brain, stimulating the body to want more and lowering weight loss success.
Because of the mechanisms of action of GLP-1 receptor agonists, high-sugar and high-carbohydrate foods can worsen nausea while taking them, as a result of increased release of insulin and other hormones. By minimizing these foods, you not only support blood glucose control and overall weight loss, but you also may help reduce nausea and vomiting.
High-Fat Foods
High-fat foods can worsen nausea for a number of reasons. First, the delayed gastric emptying that occurs as a result of taking GLP-1 receptor agonists can make heavy, high-fat foods less tolerated, as fats are slowly digested as well. Second, eating high-fat foods often causes diarrhea, worsening gastrointestinal upset. Third, taking in high-fat foods stimulates the release of cholecystokinin, bile, and other digestive hormones and compounds, which increases gastrointestinal workload and may diminish the activity of GLP-1.
Still, fats are an important part of a healthy diet, necessary for cell structure, making hormones, and nutrient absorption. While taking GLP-1 receptor agonists, focus on healthier fats, including appropriate portions of polyunsaturated fats and omega-3 fatty acids, found in foods like extra virgin olive oil, avocados, walnuts, and fatty fish.
Spicy and Highly-Seasoned Foods
Highly-seasoned and spicy foods can worsen heartburn as a result of gastroesophageal reflux disease, which is a frequent side effect of GLP-1 receptor agonist treatment already. In turn, heartburn often worsens nausea, which makes the gastrointestinal symptoms less tolerable.
Focusing on less-seasoned foods that are still nutrient-dense doesn’t have to be boring. Consider using salt, pepper, and more mild herbs and spices, like basil, oregano, parsley, paprika, and others, to impart healthy flavor without negative gastrointestinal effects.
Specific Strategies to Manage Nausea
Timing Your Meals and Medication
The most popular GLP-1 receptor agonist injectable medications can be taken independent of food intake. Interestingly, many patients report administering the injections in the thigh, rather than the abdomen, lessens associated nausea, although this is primarily anecdotal. In contrast, oral semaglutide should be taken on an empty stomach for maximum absorption.
Many patients feel an increase in nausea on the same day as each GLP-1 receptor agonist injection dose, so it can be helpful to time injections with this in mind. If you have an important event upcoming that may make managing nausea difficult, consider timing your medication dose to not coincide with that time.
Similarly, many patients experience less gastrointestinal discomfort if they don’t eat fora few hours after their GLP-1 receptor agonist injection. However, extreme hunger can cause nausea itself, so it is important to listen to your body and follow your hunger cues.
Chewing Slowly and Eating Mindfully
As schedule demands increase, eating quickly and efficiently is a common adaptation to save time. However, eating too rapidly can cause several problems. First, eating quickly makes food digestion more difficult. Inpatients taking GLP-1 receptor agonists, eating fast often worsens the associated gastrointestinal side effects. Second, eating quickly makes it hard for your stomach and brain to sense fullness. Because of the delayed gastric emptying caused by GLP-1 receptor agonists, eating rapidly limits the ability to recognize satiety, which can lead to overeating. Overeating usually leads to nausea, vomiting, and abdominal pain.
Being mindful as you eat helps recognize the flavors and nutrients of the food you eat. Completely chewing food allows digestion to begin in the mouth, easing the workload of other parts of the gastrointestinal tract and potentially improving absorption. It is important to avoid distractions (like electronics) while you eat, but rather, focus on eating as a time to savor food and nutrition.
Staying Upright After Eating
Staying upright after eating is important to facilitate digestion. Lying down after eating promotes gastroesophageal reflux and nausea. By staying upright, it helps reduce the potential nausea, vomiting, and gastroesophageal reflux disease often caused by GLP-1 receptor agonist medications.
What to remember
Gastrointestinal side effects, mainly nausea, vomiting, constipation, diarrhea, and heartburn, are common with GLP-1 receptor agonist treatment. However, there are a number of diet tips that can lessen this risk. By eating smaller, more frequent meals, staying hydrated, focusing on nutrient-dense foods, prioritizing protein, limiting foods high in sugar, carbohydrates, and unhealthy fats, and avoiding spicy and heavily seasoned foods, you may be able to improve the tolerance of GLP-1 receptor agonists.
It is imperative to speak with your physician for personalized dietary advice while you are taking a GLP-1 receptor agonist. Considering other medications, ongoing chronic illnesses, and any specific nutrient needs are all important in making the best personalized plan for optimal diet strategies.
