One could be forgiven for thinking of Ozempic, Wegovy, Mounjaro, Zepbound, Trulicity and other glucagon-like peptide-1 receptor agonists (GLP-1s) as miracle drugs. Among U.S. adults — 70% of whom count as overweight or obese — fully 12% are estimated to have used GLP-1s, and many lose 10% or more of their body weight when they do. And that’s not even the whole story.

GLP-1s, first approved for type 2 diabetes in 2005, lower blood glucose, help avoid fatty liver disease, and help with obesity-related problems such as knee pain, sleep apnea, and gastroesophageal reflux. These drugs’ improvement of triglyceride and cholesterol numbers, their lowering of blood pressure, and their reduction of strokes and heart attacks have led to the U.S. Food and Drug Administration to approve them for treating obesity as long as there’s an accompanying cardiovascular issue (in addition to the original type 2 diabetes-related approvals). And emerging research seems to back up strong anecdotal evidence that GLP-1s suppress addictive behaviors including alcohol, nicotine, and recreational drug misuse – and even lessen the pull of extreme gambling and online-shopping habits.

GLP-1s are not miracle drugs for two reasons

But there’s a key difference between GLP-1s and historic miracle drugs such as penicillin or the polio vaccine. It’s that, with GLP-1s, the user still has a big role to play in their effectiveness. Mainly, it’s about paying ongoing attention to what, and how much, they’re eating and drinking.

There are two main reasons for that. The first is that, in the short term, food choices can help avoid common side effects such as nausea and constipation as you ramp up on a GLP-1. And second, if you’re taking in fewer calories because you’re on a GLP-1, those calories need to deliver in terms of protein, fiber, and nutrients.

“The mantra for people with diabetes and without diabetes is the same: We encourage them to eat 50% of what they would normally eat without the medication,” said Shannon Christen, a UCHealth registered dietitian and diabetes educator.

Cutting back by 50%: Why deliberate nutrition matters when on GLP-1 drugs

That means paying close attention to what you’re eating, says Christen, who works with patients in UCHealth’s Endocrinology and Diabetes Clinic as well as the University of Colorado School of Medicine’s Cardiometabolic and Advanced Lipid Disorder Clinic at UCHealth University of Colorado Hospital on the Anschutz Medical Campus.

“It’s got to be really intentional and nutritious,” she said. “Because, if you’re only able to eat 50%, you should make every bite as nutritious as possible – protein, fiber, and hydration is the name of the game.”

The nature of GLP-1s makes caloric cutback easier than it sounds. They suppress “food noise,” which UCHealth registered dietitian Erin Cahoon described as “a constant nagging to eat something – you just can’t stop thinking about food. A GLP-1 receptor agonist quiets that.”

So, what should you eat, and what else should you pay attention to when you’re on GLP-1s?

Prioritize protein on GLP-1

The goal here should be about 1.2 grams of protein per day per kilogram of body weight (or 0.55 grams of protein per pound of body weight), Christen says. For a 150-pounder, that’s 82 grams a day. Protein could come in the form of eggs, fish, chicken, Greek yogurt, cottage cheese, tofu, beans, or protein shakes (Cahoon, for example, refers patients to high-protein smoothies such as these.)

Fiber up for better health

Fiber is important for everybody. It’s a prebiotic, promoting the growth of beneficial gut bacteria. It also helps avoid constipation, one of the most common side effects of GLP-1s. Foods such as oats, berries, whole grains, leafy greens, and lentils are good sources of fiber, but Cahoon suggests that, because many of us get too little dietary fiber, psyllium-based supplements such as Culturelle, Benefiber, Healthy Origins, and Metamucil can help.

Hydrate to help with side effects – ideally with water or zero-calorie drinks

Constipation and nausea are the most common side effects of GLP-1 use – particularly when starting off on the drugs. Staying hydrated can help mitigate both, say both Christen and Cahoon. GLP-1s can make that harder, because, just as they suppress appetite, they dial back your sense of thirst. Shoot for eight to 10 glasses of water or sugar-free beverage a day.

Small, frequent meals for GLP-1 users

Your stomach empties into your intestine slower when you’re on a GLP-1. Large meals can lead to discomfort and nausea.

Rather than two or three big meals, consider three smaller meals supplemented with healthy snacks.

“Maybe five or six times a day, you’re eating something little, but you want it to be balanced,” Cahoon said, with a protein, a fruit or vegetable, and whole grain starch or similar. A protein-rich, low-sugar smoothie can be a great choice for a snack, she added. (Cahoon suggests trying these.)

Smaller, more frequent meals can also help those on GLP-1s who are also taking diabetes medications avoid getting overly hungry and ending up with too-low blood sugar (hypoglycemia), Christen adds.

Christen also emphasizes the importance of eating slowly. It takes about 20 minutes for the brain to recognize the full extent of a meal. Eating quickly puts those on GLP-1s at risk overeating and then suffering with consequences.

If you do end up with nausea, Cahoon recommends ginger tea, either from a tea bag or by slicing ginger root into thin coins and steeping them.

Avoid greasy foods, sugary and ultraprocessed foods, and alcohol while you adjust

Greasy foods such as fried foods and fast food can make nausea and digestion worse, so baking, grilling, steaming, or roasting is a better idea, particularly early in your GLP-1 journey.

“If we’re eating a lot of greasy food and we’re nauseous already on these GLP-1 agonists, that’s not going to do us any favors,” Cahoon said.

Sugar and ultraprocessed food combine a general lack of nutrition with the risk of blood sugar spikes and crashes, which can put those on diabetes medications at higher risk and cause nausea, fatigue, and cravings in general.

“Alcohol and refined carbs and sugars are not nutrient-dense, so they’re going to fill us up, and then we’re going to miss out on eating something that truly nourishes us,” Cahoon says.

Go for a walk

Walking, running and other types of exercise are important for everyone; those on GLP-1s find that it helps with constipation in particular.

If you’re suffering, check with your doctor

If going on a GLP-1 suppresses your appetite to the point that you’re not interested in eating at all, or if you’re vomiting frequently or severely constipated, reach out to your provider: Your GLP-1 dosing may need to be lowered.

Stay engaged. Nourish your body with plenty of nutritious foods.

GLP-1s are delivering profound weight loss and diverse, positive health impacts. But you have to stay engaged to help them help you. What you eat is a big part of that.

“GLP-1 agonists are a tool to support you on your health journey,” Christen says. “You still have to nourish your body with enough fuel — and the right fuels — to perform.”