62. GLP-1s: What Nutrition Professionals Need to Know Right Now

June 9, 2026

If you are a registered dietitian or nutrition professional in private practice, your clients are on GLP-1 medications. Some have told you. Some have not. Some assume it is outside your scope. Some simply did not think to bring it up.

Either way, the nutritional support they need is not coming from the prescribing physician. That is not a criticism – it is a scope reality. And it means there is a significant gap in care that you are uniquely positioned to fill.

This is not a trend you can afford to wait on. GLP-1 receptor agonists have moved from diabetes management into mainstream weight management at a pace that has reshaped the clinical landscape for nutrition professionals. The practitioners who get fluent in this now will be the ones their clients turn to – and stay with – for years.

Here is what you need to know.

What GLP-1 Medications Actually Do

GLP-1 – glucagon-like peptide-1 – is an incretin hormone your body produces naturally in response to eating. GLP-1 receptor agonists like semaglutide and tirzepatide mimic and amplify that response. They enhance insulin secretion, suppress glucagon, slow gastric emptying, and increase satiety. They also act on the brain’s appetite and reward centers, which is why so many patients describe the experience of food noise going quiet for the first time.

A 2025 systematic review of over 15,000 participants across 26 randomized controlled trials found weight loss of up to 22% with the newest agents over approximately one year. These are significant clinical results, and they explain why prescriptions have exploded across primary care, endocrinology, telehealth platforms, and weight loss clinics.

The barrier to access has dropped. The number of people on these medications is growing. And the nutritional support most of them are receiving is essentially zero.

The Nutritional Risk Your Clients Are Facing

Here is what practitioners need to understand: weight loss on a GLP-1 medication is not automatically healthy weight loss.

The medication does its job effectively – it reduces appetite and helps patients eat significantly less. Research shows caloric reductions of 16 to 39 percent in this population. But when someone is eating that much less, the body does not automatically burn fat. It will also pull from muscle tissue if the right nutritional guardrails are not in place.

Without structured nutritional support, GLP-1 patients are at real risk for muscle loss, protein deficiency, nutrient depletion, and inadequate hydration. Your job is not to manage the medication. It is to protect the patient while the medication does its work.

There are three things every GLP-1 client needs but probably isn’t getting.

Adequate protein. The general population recommendation is 0.8 grams per kilogram of body weight per day. For patients on GLP-1 medications – in a caloric deficit, losing weight rapidly, and at elevated risk for muscle loss – the research supports a target of 1.2 to 2.0 grams per kilogram per day. For a patient who weighs approximately 220 pounds, that means 120 to 200 grams of protein per day, depending on activity level and rate of weight loss. Getting there is a real challenge when appetite is suppressed, which is why 1.2 g/kg is the floor, and the target moves upward based on what the patient can realistically consume. Protein first at every meal and snack, 20 to 30 grams per meal, high-quality sources, and protein shakes or smoothies as a clinical bridge when food intake is particularly low.

Consistent hydration. GLP-1 medications slow gastric emptying, which means food and fluids stay in the stomach longer. Patients feel full very quickly – and that fullness applies to water too. They end up drinking less without realizing it, which compounds every GI side effect. The baseline goal is 64 fluid ounces of water per day, sipped consistently rather than in large amounts at once. Large volumes of liquid can worsen nausea. Water-rich foods like cucumbers, watermelon, soups, and broths count toward fluid intake. Light yellow or clear urine is the target – dark yellow means more fluids are needed.

Structured meal timing. GLP-1 medications suppress hunger signals so dramatically that many patients stop eating on a regular schedule. They feel fine, they are not hungry, they skip a meal – and over days and weeks, that adds up to real nutritional gaps. Patients need to eat by the clock, not by hunger. Three meals plus one to two planned snacks daily, smaller and more frequent eating occasions rather than large meals, and protein prioritized first at every eating occasion. The reframe that works with patients: eating on a schedule on a GLP-1 is not about being hungry. It is about giving the body a consistent supply of the building blocks it needs to stay strong during weight loss.

The Nutrient Deficiencies You Need to Have on Your Radar

With caloric intake dropping 16 to 39 percent and GI side effects like nausea, vomiting, and delayed gastric emptying in the picture, patients are not just eating less – they are absorbing less efficiently too. That combination is what creates real deficiency risk.

The priority nutrients to monitor and address for every GLP-1 client:

B12 deserves special attention for any client also on metformin. Metformin is well-documented to deplete B12 with long-term use, and that risk compounds when overall food intake is also reduced. Any patient on both medications should have B12 monitored in labs and supplemented proactively. This is not a population where waiting for symptoms is appropriate.

Iron absorption is affected by both reduced intake and the GI environment on these medications. Pair iron supplementation with a vitamin C source – vitamin C significantly enhances absorption of non-heme iron, the type found in most supplements and plant foods. Keep calcium and iron separated by at least two hours, because calcium actively inhibits iron absorption even in small amounts.

Fat-soluble vitamins – A, D, E, and K – require dietary fat to be absorbed. Patients on GLP-1 medications are eating less, and many are actively avoiding fat to manage nausea. Fat-soluble vitamins taken on an empty stomach or with a very low-fat meal may not be absorbed effectively. Always recommend taking fat-soluble vitamins with a meal that includes a healthy fat source – a small amount of olive oil, avocado, nuts, or fatty fish is sufficient.

Magnesium is one of the most useful yet underutilized tools for managing constipation in this population. Magnesium draws water into the bowel, supporting motility and softening stool. Magnesium citrate or magnesium glycinate is well tolerated. Start low and titrate up based on response.

Zinc and calcium are both at risk given reduced overall food intake and impaired absorption. A high-quality multivitamin and multimineral is the baseline recommendation for every GLP-1 patient, regardless of which medication they are on. This covers the broad spectrum of nutrients most at risk and provides a solid foundation for targeted supplementation.

Omega-3s are worth monitoring too. Patients often stop eating fatty fish because high-fat foods worsen nausea, so omega-3 levels can quietly decline. EPA and DHA have strong anti-inflammatory evidence, and this population is already managing metabolic inflammation.

Managing GI Side Effects Through Nutrition

GI side effects are the most common reason patients reduce their dose, pause their medication, or stop entirely. Your ability to give patients practical dietary strategies for managing nausea, constipation, and diarrhea is genuinely treatment-supporting.

Nausea is the most common GI side effect. It is most likely in the first few weeks of starting the medication and after each dose increase – communicate this to patients proactively so they are not caught off guard. Dietary strategies include eating smaller, more frequent meals; eating slowly with small bites and pauses between them; choosing gentle, easy-to-digest foods like plain oatmeal, scrambled eggs, and broth-based soups; avoiding strong smells, high-fat foods, and spicy foods; trying ginger or mint tea; and sipping fluids steadily throughout the day. Most patients find nausea improves meaningfully within two to four weeks at a stable dose.

Constipation is common and often persistent – it builds gradually and patients do not always connect it to the medication. GLP-1 medications slow movement through the entire digestive system, not just the stomach. Combined with reduced fluid intake, less food overall, and lower fiber, constipation can become an ongoing management challenge. Key strategies: increase fluids to eight to ten glasses per day, increase insoluble fiber slowly and one food at a time, stay physically active with even light movement after meals, eat regular meals to keep the digestive system active, and include probiotic-rich foods like yogurt and kefir. If dietary strategies alone are not managing symptoms, that is a signal to loop in the prescribing physician.

Diarrhea is less common but distressing enough that patients often want to stop the medication. Hydration with electrolytes is the immediate priority – plain water is not sufficient when there is significant fluid loss. Focus on soluble fiber sources like oats, bananas, applesauce, and chia seeds. Avoid coffee, alcohol, carbonated drinks, and products containing sugar alcohols like sorbitol and xylitol, which are commonly found in sugar-free products and protein bars. Most patients see diarrhea improve within the first few weeks as the body adjusts.

The Weight Regain Reality

This is the conversation most practitioners are not having – and it is the one that determines long-term outcomes.

When patients stop GLP-1 medications without a strong nutritional and behavioral foundation in place, the majority regain a significant portion of the weight they lost. The medication was doing enormous work – suppressing appetite, slowing digestion, quieting food noise. When it is gone, those effects go with it, and hunger returns.

The clients who hold their results are the ones who used their time on the medication to build real habits. Consistent protein intake. Regular meal timing. Meal prepping so food is ready when appetite and energy are low. Balanced plates are built around protein first. Resistance training established before the medication is tapered.

GLP-1 medications also create a genuine opportunity for mindful eating that is worth building intentionally. Many patients describe the quieting of food noise as the first time they have been able to tune into real hunger and fullness signals. That skill will serve them long after the medication is gone.

The de-escalation process matters. A structured framework moves through three phases: foundation building while on a stable dose, gradual dose reduction every four to six weeks with intensive monitoring, and medication-free maintenance with long-term metabolic monitoring. Coming off a GLP-1 is not a stop date. It is a transition that requires proactive preparation.

Key de-escalation principles for practitioners to build into their protocols:

Do not reduce calories further as the medication tapers. Hunger will return, and clients need a sustainable eating pattern they can actually maintain. Keep protein targets elevated at 1.2 g/kg or above to preserve lean muscle mass and support satiety as appetite returns. Explicitly prepare clients for hunger and food noise returning before the taper begins. And make sure resistance training is an established habit before the medication is gone – the research is increasingly clear that strength training is one of the most powerful tools for maintaining weight loss after GLP-1 discontinuation.

Why This Is Your Opportunity

The prescribing physician is handling the medication. Nobody is handling the nutrition.

Patients on GLP-1 medications need structured nutritional support, targeted supplementation, GI side-effect management, meal-planning resources, and a practitioner who can guide them through de-escalation while preserving their results. That is exactly what nutrition professionals are trained to provide.

The practitioners who become fluent in GLP-1 support now will be the ones their clients stay with, refer to, and return to. This is not a niche offering. It is becoming a core competency for nutrition professionals in private practice.

Your Content Cure

Your Content Cure for this episode is access to our free GLP-1 Masterclass and content bundle. Register to join us live on June 11th and get the recording plus a free bundle of resources you can use directly in your GLP-1 client work. We are going deep on everything covered in this post – the clinical picture, the nutrition protocols, the supplement strategies – with a Fullscript medical expert.