If you take semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound) to treat obesity, you may want to rethink what you eat. This class of drugs, known as GLP-1s, is the newest type of prescription obesity medication. They're hailed for their ability to also slow down digestion and send “I’m full” signals to the brain.
But for some people, those effects can go too far. “It works so well that they forget to eat,” says Vijaya Surampudi, MD, clinical chief of the Division of Clinical Nutrition at UCLA Health and associate director of UCLA’s weight management clinic. “We're actually seeing cases of malnutrition and dehydration.”
There’s no specific “Ozempic diet” that’s recommended for these weight loss drugs. But because many people eat fewer calories while using the medications, it’s important that they choose nutritious foods.
To keep the weight off for the long term, it can also help to know that these drugs are best used in tandem with healthy eating and exercise. “It requires a complete lifestyle change. There’s just no easy way around it,” says Geri Lynn Grossan, a registered dietitian nutritionist and certified diabetes educator in Las Vegas.
Following a healthy diet – which includes lots of lean protein and vegetables and limits processed foods – is the best way to lose fat, build muscle, and feel good while doing it, Grossan says. “Think about what your grandma was eating 50 years ago.”
Grossan and Surampudi shared the following advice on foods to eat and to avoid when using this type of weight loss drug.
This interview has been edited for length and clarity.
How do GLP-1 agonist drugs like Ozempic work?
Vijaya Surampudi, MD: We're still learning about how they work, but simplistically, I think of it in three ways.
One, they work in the way that we initially brought them to light with diabetes medications: They tell the pancreas to release more insulin, depending on what your blood glucose is.
Two, they slow digestion down.
Three, they also seem to have an effect on the brain, where they're actually quieting the brain down a little bit and helping you not think about food as much. So some people might say, ‘I feel full longer,’ and ‘I'm not thinking about food as much,’ which makes it easier for them to make the food choices that they would like to make.
When it comes to nutrition, what should the priorities be?
Geri Lynn Grossan: Because these medications reduce your appetite and you can't eat as much, and because food stays in your stomach longer so you stay full longer, it's really important to make sure the food that you are eating is very high nutritional quality.
Protein is going to be the most important nutrient because it's not something that we store. Knowing that, you should eat the protein first, so if you get full quickly, you’ve had at least a few bites of that. If you aren't eating enough protein throughout the day – and actually with each meal – then your muscles are going to start breaking down.
And then fruits and vegetables are great. Whole grains, beans, lentils, and legumes are great. Nuts would be good. All the healthy stuff we need.
Medical reviewer's note: Eating smaller meals balanced with protein, produce, whole grains, and nuts is the best approach.
Surampudi: Good sources of protein are the most bioavailable sources. Eggs, chicken, and fatty fishes are great sources of protein. If you’re more plant-based or you prefer to avoid animal products, look at things like tofu, edamame, and tempeh, which are all soy products. You can also get protein out of lentils and some beans.
Medical reviewer's note: Whole grains and nuts are additional plant-based protein sources.
Vegetables are another priority, and the key is diversity of color. Each color represents a different phytonutrient. If you've got three different-colored bell peppers, you're getting three sets of different phytonutrients. That doesn't mean every plate has to look like a rainbow, but throughout the week make sure you’re varying your vegetables.
With starchy vegetables, treat them like a carbohydrate and moderate how much you’re eating.
Water is also important. Not only does it curb hunger, but people sometimes forget that they're thirsty, so they're not drinking enough water.
Dr. Surampudi, I noticed you did not say fruit.
Surampudi: Fruit over the years has gotten very, very sweet. It has a higher carbohydrate count than once upon a time, so I usually recommend no more than two fruits per day, and people should view it more as a dessert or a snack.
Medical reviewer's note: Fruits lower in sugar include raspberries, strawberries, kiwi, grapefruit, blackberries, watermelon, peaches, cantaloupe, and oranges. The 2020-2025 U.S. Dietary guidelines recommend 1.5-2 cups of fruit per day for adults. Keep in mind that you get fiber, phytochemicals, vitamins, and minerals when you eat fruit.
Are there specific foods people should avoid?
Surampudi: This drug slows your digestion down. So some of the side effects – we're talking about nausea, vomiting, constipation, diarrhea – are actually affected by the types of food you eat.
Fats take a longer time to digest, so they already naturally spend a longer time in the stomach. So if you have an external stimulus that's slowing your digestion down, and then you have fat sitting in your stomach even longer, it might make you feel more nauseous. Avoiding very highly processed fatty foods and deep fried foods can be helpful in reducing those symptoms.
How does someone know if they're eating enough calories?
Grossan: Part of it is how fast are they losing weight? Two pounds a week is really the safe, recommended weight loss. So if you're losing more than that, you probably aren't getting enough calories in the day.
And also, how do you feel? If you wake up and you don't have a lot of energy throughout the day, then that means your body's metabolism has probably slowed down too much because maybe you need 2,000 calories, but you're only getting 1,000 calories because you're just not that hungry.
What should people consider when it comes to things like alcohol and coffee?
Surampudi: Alcohol can play a funny role. It can worsen side effects for some people, like nausea and vomiting. There is a slight concern about whether it can set people up for further hypoglycemia; alcohol can lower blood sugar for people because it prevents the liver from pushing up glucose in the bloodstream. If people are going to drink, stick with the guidelines, which state two or fewer drinks a day for men and one or less for women.
As far as coffee, I don’t have a problem with it if you’re just drinking coffee. It’s all the extra dressings [sugar, cream, etc.] that get people in trouble.
What advice can you share with someone who has overindulged or is experiencing a lot of side effects?
Surampudi: Listen to your body. For overindulgence, take a walk. It helps with motility and getting the food to digest a little bit more.
If you’re experiencing a lot of side effects, you might want to talk to your doctor about making dose adjustments because the higher the dose, the more likely you’ll have more side effects.
Grossan: If you’re feeling nauseous or experiencing gastrointestinal issues, you’ll want to go bland with your foods: crackers, toast, rice, soup. You’ll also want to stay away from things that are really spicy because the spice might be aggravating.
Are there other actions a person can take to feel confident they’re getting quality nutrition while using these medications?
Grossan: I think people need to have at least one appointment with a registered dietitian, and that’s something that many insurance plans will cover if a person has a diagnosis of obesity.
When I meet with clients, I get a complete history and ask them to track what they eat for 3 days. Then I educate them and set up a meal plan based on the foods they like and their lifestyle, so they leave knowing what to eat.
Common sense really isn't that common with eating anymore. If you consider that 20, 30 years ago was when all of the really processed food came into being, that may mean that if you’re 40 years old, you may have grown up not knowing what real food is. And real food means going back to the basics.
What future developments can we expect on the weight loss front?
Surampudi: I think this is just the beginning. I think these medications are going to be an incredible tool in weight management. But it's important to remember it’s just that: a tool in the toolbox, and we still need to prioritize diet and exercise.
I always say that medications are there to fight genetics. Diet and exercise are there to help fight what we do to ourselves. You need all those things. Some people may need medication, they may need weight loss surgery, they may need diet and exercise. It’s not mutually exclusive. We’ve got to use all of it together to help you be the most metabolically healthy person you can be.
