GLP-1 weight loss drugs like semaglutide (Ozempic) and tirzepatide (Mounjaro) have hit the scene like veritable gifts from heaven for folks struggling to steady their blood sugar and lose weight. According to research, these pharmaceuticals really do what they say, helping to tackle stubborn weight and bringing hemoglobin A1C (the gold standard measure of blood sugar) into a healthier range. A large 2021 study in the New England Journal of Medicine even found that people with overweight or obesity who took a once-weekly semaglutide injectable for a year lost an average of 14.9 percent of their body weight. Other studies (like this one and this one) have confirmed that these drugs significantly decrease A1C.
Still, it’s not necessarily all sunshine, rainbows, and showing off smaller pant sizes when you’re on one of these medications. As more and more people use them, reports are emerging that they can cause nutrient gaps—or even outright deficiencies.
If you’re taking a GLP-1, it’s important to be mindful of these possible outcomes. Nobody wants to end up feeling sick due to nutrient deficiencies. After all, you’re probably on GLP-1s to feel better.
Here’s a look at why dietary gaps may happen on GLP-1s, and how you can keep your nutrition going strong.
- ABOUT OUR EXPERTS: Alyssa Pacheco, R.D., is a registered dietitian. Dr. Miranda LaBant, N.M.D., is a naturopathic doctor. Brian Tanzer, M.S., is a nutritionist and the Director of Scientific and Regulatory Affairs for The Vitamin Shoppe. Brittany Michels, L.D.N., R.D.N., C.P.T., is a registered dietitian, certified personal trainer, and an in-house nutritionist for The Vitamin Shoppe.
Why You Might End Up With Nutritional Gaps on GLP-1s
GLP-1 agonists work on several fronts within your GI tract and even your brain. They activate receptors in the pancreas that release insulin, block the secretion of glucagon, slow stomach emptying, and send signals of fullness to the brain. By firing on all these cylinders, the drug makes you feel significantly less hungry. Some users say that even the little “pocket” of appetite they might keep for a post-dinner dessert or afternoon snack simply goes away.
Read More: 7 Sneaky Things That Can Mess With Your Appetite
Of course, this vanishing appetite is exactly why weight loss occurs, which is also why it’s not great for maintaining proper levels of nutrients. “With a decreased appetite, people typically eat fewer calories than their body needs, which leads to weight loss,” says Alyssa Pacheco, R.D. “With a significant reduction in calories, though, it can be easier for someone to fall short on getting adequate nutrients into their diet.”
Meanwhile, since GLP-1 side effects can include nausea, vomiting, stomach pain, and diarrhea, you may also feel too woozy to eat a regular diet (at least until these pass). For most people, side effects are short-lived, Pacheco says, but if they go on long enough, it’s possible that they could create malnutrition. (More on how to support your digestive system through the transition to come.)
Nutrients You’re Mostly Likely To Fall Short On
So…if your intake has dipped from low appetite, which nutrients are you most likely to miss? We don’t know with 100 percent certainty just yet, since not enough research has been conducted on the subject yet, says nutritionist Brian Tanzer, M.S., Director of Scientific and Regulatory Affairs for The Vitamin Shoppe. What we do know, according to data from the CDC, is that the most common nutrient deficiencies in the general population are vitamin B6, iron, vitamin D, and vitamin C. Since everyday folks are more likely to lack these nutrients to begin with, insufficiency may be even more likely (or exacerbated) by GLP-1 use. “Nutrient deficiencies [like these] may become more prevalent as more people are prescribed these medications,” says Tanzer.
Some experts say other specific deficiencies may be likely, too. According to Pacheco, protein, folate, and vitamin B12 may also be of concern.
Meanwhile, naturopath Dr. Miranda LaBant, N.M.D., worries about fat-soluble vitamins (which include vitamins A, D, E, and K). “Since weight loss can impact the absorption of fat-soluble vitamins, monitoring and supplementation may be necessary to prevent deficiencies,” she says.
How to Know If You’re Low
Nutrient deficiencies can show up with all sorts of symptoms, from increased anxiety to fatigue. If you feel like something is off with your health, it’s always a good idea to visit your doctor, rather than self-diagnose. The only way to know for certain whether you’re dealing with a nutrient deficiency is to have a blood test, Tanzer says.
Read More: 4 Nutrient Deficiencies That Can Lead to Low Mood
If it turns out that you do have a deficiency related to a medication like Ozempic or Mounjaro, you’ll want to stay in close collaboration with your doctor, even after initial testing. This can keep nutrition gaps from becoming dangerous. “Regular assessments of nutrient levels, especially for fat-soluble vitamins, can help identify and address potential deficiencies early on,” LaBant says.
How to Fill Nutritional Gaps While Taking a GLP-1
Fortunately, you’re not without options when it comes to checking all your nutritional boxes on GLP-1s. Here’s how you can avoid falling short:
1. Eat at regular intervals
Simply scheduling your meals at regular times can keep you from skipping them—and ultimately missing out on important nutrients. “This may seem difficult if you don’t have much of an appetite, but meals don’t have to be big,” says Pacheco. “You can even incorporate smaller meals or snacks throughout the day.” Try planning for meals and snacks every two to six hours.
2. Prioritize protein
One nutrient rises to the top of the heap for deficiency prevention: protein. Not only does protein preserve muscle mass while you’re losing weight, but it’s also a great meal starter. Build meals and snacks around a healthy source of protein like beans, eggs, or chicken breast, then round out your plate with complex carbs and good-for-you fats. (Check out these dietitian-approved high-protein snacks, if you need some inspiration.) Protein powders are also easy to add to smoothies and shakes for a nutritional boost.
3. Add a Multi to Your Morning
If you’re concerned about meager micronutrients, adding a well-rounded multivitamin to your routine is a simple way to up your intake and hopefully avoid insufficiency. If your blood tests show you’re low on specific nutrients (like vitamin D or iron), your healthcare provider might advise you to snag a higher-dose supplement to get you back in the black.
4. Consult with a dietitian
You don’t have to go it alone here! Speaking with a nutritionist (especially one who’s knowledgeable about semaglutides) will give you the guidance you need to lose weight and control your blood sugar without missing out on critical nutrients. The Vitamin Shoppe offers free nutrition coaching for all Healthy Awards members.
How To Soothe Gastrointestinal Side Effects
Though they typically subside with time, mild to moderate gastrointestinal symptoms occur in most people getting started with GLP-1s, notes The Vitamin Shoppe nutritionist and registered dietitian Brittany Michels, R.D.N., L.D.N., C.P.T. The most common of these side effects include general discomfort, abdominal pain, nausea, vomiting, diarrhea, and constipation—pretty much the whole gamut.
There are a couple of reasons for the less-than-pleasant symptoms, one being the fact that these medications delay the movement of food through the digestive tract, Michels explains. Not only can this slow movement create discomfort and nausea, but it may also impact your ability to eat enough fiber, which then snowballs digestive issues by contributing to constipation, she says.
Not to mention, “any change in digestive tract movement may influence our gut microbiome, specifically by decreasing beneficial bacteria and increasing bad bacteria,” adds Michels. Shifts in this complex and delicate ecosystem can also ladder up to miserable GI symptoms.
Again, thankfully many of these side effects tend to fade on their own, but there are still a few things you can do to support your body through the transition—and promote gut health long term.
1. Choose Easily digestible Foods
If uncomfortable side effects are keeping you from eating much, choose your foods wisely. “Opting for easily digestible and nutrient-rich foods, such as steamed vegetables, lean proteins, and whole grains, can enhance nutrient absorption and promote gastrointestinal comfort,” says LaBant. On the flip side, avoiding harder-to-digest foods like anything greasy or fried, as well as ultra-processed items like cookies, chips, or candy, which lack the nutrients you need, can also help your system settle.
2. Be Mindful of Your Fiber Intake
Fiber works to support regular digestion (plus gut health, immune health, and more) in multiple ways—and the loss of appetite and feelings of fullness many GLP-1 users experience can tank fiber intake significantly (and lead to or worsen GI side effects), according to Michels. “Since too little or too much fiber may cause constipation, it would be beneficial to assess intake prior to making changes,” she explains. “However, if food intake is down, then it is likely you’ll need a fiber supplement to meet daily goals.” Scheduling a complimentary consultation with one of The Vitamin Shoppe’s credentialed nutritionists is a good way to gauge where you’re currently at with fiber intake.
If you do, indeed, need to get more fiber into your system, consider incorporating an unflavored powdered fiber supplement, like Garden of Life Raw Organic Fiber, which can be easily added to all sorts of beverages and other recipes, such as oatmeal and smoothies. Slow and steady is the name of the game here, so work with your nutritionist or another healthcare provider to increase your intake over the course of a few weeks until you reach your daily goal. (If you’ve struggled with taking fiber in the past, these tips can make supplementing more pleasant.)
3. Consider Supplementing with Probiotics
It’s no secret that probiotics are essential for a healthy digestive system. After all, probiotic foods have been staples in cultures across the globe for generations upon generations. Because of the impacts that GLP-1s can have on the gut microbiome—and the digestive side effects that follow—a probiotic supplement (such as ProBioCare Women’s Once Daily or ProBioCare Men’s Once Daily) may be beneficial for users who want to support their system as best they can, Michels explains. A daily probiotic may be especially helpful if changes in appetite and other symptoms reduce a user’s intake of probiotic-rich foods, such as fermented dairy or vegetables.