GLP-1 Medications and Medical Nutrition Therapy: What People Need to Know

What Are GLP-1 Medications?

Glucagon-like peptide-1 receptor agonists (often shortened to "GLP-1 medications") are a class of injectable or oral drugs originally developed to treat type 2 diabetes. They mimic the effects of the natural gut hormone GLP-1, which helps regulate blood sugar, appetite, and digestion.¹

Common GLP-1 or related incretin-based medications you may hear about include:

• Semaglutide (for example, Ozempic®, Wegovy®)
• Liraglutide (for example, Saxenda®)
• Dulaglutide (Trulicity®)
• Tirzepatide (Mounjaro®, Zepbound® – a dual GIP/GLP-1 agonist)

These medications are now used for two main indications:

• Type 2 diabetes management: lowering blood glucose and A1C.
• Chronic weight management in people with obesity or overweight and weight-related conditions.^1,2

A growing body of research also shows that GLP-1 receptor agonists can reduce the risk of major cardiovascular events in people with type 2 diabetes and high cardiovascular risk, leading some guidelines to consider them part of "cardiometabolic" therapy rather than blood-sugar treatment alone.^2,3

How GLP-1 Works in the Body

GLP-1 is one of the body's "incretin" hormones. It is released from the gut after eating and sends signals that influence blood sugar control, appetite, and digestion.^1,4 GLP-1 receptor agonist medications amplify these signals.

Key actions of GLP-1 medications include:

• Stimulating insulin secretion from the pancreas when blood glucose is elevated.
• Reducing glucagon secretion, which lowers the liver's glucose output.
• Slowing gastric emptying, so food leaves the stomach more slowly.
• Acting on the brain to decrease appetite, reduce food cravings, and support a lower energy intake.^1,2,4

Together, these actions help:

• Improve blood glucose control.
• Support weight loss in many individuals.
• Improve cardiometabolic risk factors such as blood pressure and lipids in some populations.^2,3,5

New dual- and triple-agonist drugs (acting on GLP-1 and additional gut hormone receptors) are in development and may provide even greater weight loss and metabolic benefits, although long-term data are still emerging.^4,6

Who Might Be Offered GLP-1 Therapy?

Prescribing decisions are always made by a licensed medical provider, based on clinical guidelines, medical history, and shared decision-making. In general, GLP-1 medications may be considered for:

• Adults with type 2 diabetes who need additional glucose lowering or cardiometabolic benefit.
• Adults with obesity (for example, BMI ≥ 30 kg/m²) or overweight with weight-related conditions (such as hypertension, sleep apnea, or prediabetes), when lifestyle interventions alone have not been sufficient.^1,2,5

In 2025, the World Health Organization issued guidance supporting the use of certain GLP-1 and related incretin therapies (such as semaglutide, tirzepatide, and liraglutide) for long-term obesity treatment in adults, alongside healthy eating and physical activity. These recommendations are "conditional," reflecting important uncertainties about cost, long-term safety, and health-system capacity, and they specifically exclude use during pregnancy.⁷

These medications are not appropriate for everyone. They have contraindications (for example, personal or family history of certain endocrine tumors or pancreatitis) and potential side effects that must be reviewed with a prescriber. They should never be started without medical evaluation and ongoing monitoring.

Common Side Effects and Safety Considerations

Because GLP-1 medications slow gastric emptying and act on the gut–brain axis, gastrointestinal symptoms are very common, especially during dose escalation. Frequently reported side effects include:^1,5,8

• Nausea.
• Vomiting.
• Diarrhea or constipation.
• Abdominal discomfort.
• Reduced appetite or early fullness.

These symptoms can often be mitigated through gradual dose increases and targeted nutrition strategies (such as smaller, more frequent meals and attention to fluid and protein intake), but they can occasionally lead to treatment discontinuation or complications like dehydration.^5,8,9

Rare but serious concerns that clinicians watch for include:

• Acute pancreatitis.
• Gallbladder issues.
• Severe gastrointestinal symptoms or obstruction-like presentations.

Regulators in several countries have also issued safety communications about potential mental-health adverse events, including reports of suicidal ideation in people taking GLP-1 and related incretin drugs, although a clear causal link has not been established. Current guidance emphasizes careful monitoring, especially in individuals with a history of depression or suicidal thoughts, and prompt medical evaluation if symptoms emerge.^10,11

Some incretin therapies can interfere with the absorption of oral contraceptives, particularly around dose changes, which is why certain regulators advise backup or non-oral contraception in people of child-bearing potential using tirzepatide-based medications.^10,11

Because substantial and rapid weight loss can affect gallbladder function, bone density, lean mass, and mental health, medical supervision and nutrition support are essential throughout treatment.^5,8,9

Why Nutrition Still Matters on GLP-1 Therapy

GLP-1 medications can significantly reduce appetite, make smaller portions more satisfying, and help lower overall energy intake. But they do not automatically guarantee that the food choices people make are balanced or nutrient-dense. In fact, several recent reviews emphasize that nutrition quality becomes more important, not less, during GLP-1 treatment.^5,8,9,12

Key nutrition priorities during GLP-1 therapy include:

• Preserving lean body mass (muscle and bone) by ensuring adequate protein intake and pairing medication with resistance training where appropriate.^5,8,13
• Managing gastrointestinal side effects through meal timing, portion sizing, hydration, and tailoring the composition of meals.
• Preventing micronutrient shortfalls when total food volume is lower (for example, maintaining intake of iron, B-vitamins, calcium, vitamin D, and essential fatty acids).
• Supporting cardiometabolic health with dietary patterns that improve blood pressure, lipids, and inflammation, not just weight.
• Addressing emotional and behavioral aspects of eating, including long-standing patterns of restriction, overeating, or emotional eating that medications alone cannot resolve.^5,9,12

Leading professional and research groups now call nutrition and lifestyle counseling a "missing pillar" in many GLP-1 care pathways and argue that structured support from registered dietitians should be standard, not optional, for people receiving these medications.^9,12,14,15

The Role of Registered Dietitians in GLP-1 Care

Registered dietitian nutritionists (RDNs/RDs) bring expertise that complements medical management. The Academy of Nutrition and Dietetics and other professional bodies highlight that individuals using obesity medications should have access to evidence-based lifestyle interventions and medical nutrition therapy to optimize outcomes and address the complex drivers of obesity.^14,16

In the context of GLP-1 therapy, a dietitian can help with:

• Pre-treatment counseling: clarifying realistic expectations for weight loss, discussing lifestyle foundations, and reviewing current eating habits before medication starts.
• Early dose-escalation support: adjusting meal patterns as nausea or early fullness emerges; prioritizing protein and hydration; identifying trigger foods that worsen symptoms.^5,8,13
• Body-composition protection: designing meal plans and snack strategies that support muscle maintenance, especially when appetite is low and physical activity may be changing.^5,13
• Long-term maintenance: helping people transition from initial weight loss to weight stability, with emphasis on sustainable behaviors rather than short-term restriction.
• Equity and access: tailoring guidance to budget, cultural preferences, schedules, and cooking skills so that nutrition recommendations are realistic and respectful of lived experience.^9,12,14

Studies suggest that people on GLP-1 medications who receive structured nutrition guidance lose more weight and report better quality of life than those who receive medication alone.^12,15 This reinforces the idea that medication and medical nutrition therapy are most effective when used together.

Practical Nutrition Strategies for People on GLP-1

Every person's needs are different, and specific plans should be created with a qualified professional. However, many dietitians working with GLP-1-treated patients focus on a few core principles:

1. Prioritize Protein at Each Meal

With reduced appetite, it becomes easier to under-eat protein. Adequate protein intake helps preserve lean mass and supports satiety. Many experts encourage including a protein source (for example, eggs, yogurt, beans, tofu, fish, poultry, or lean meats) at each meal and some snacks, adjusted for individual kidney function and medical conditions.^5,8,13

2. Emphasize High-Quality, Lower-Volume Foods

When stomach capacity feels limited, nutrient density matters. Dietitians often guide clients toward:

• Vegetables and fruits in tolerable portions and textures.
• Whole grains, beans, and lentils where GI symptoms allow.
• Healthy fats from nuts, seeds, olive oil, and fatty fish.
• Fermented foods such as yogurt or kefir for gut support, if tolerated.¹⁷

3. Eat Slowly and Stop at Comfortable Fullness

Because GLP-1 medications slow gastric emptying, eating quickly may increase nausea or discomfort. Many clinicians recommend:

• Smaller, more frequent meals.
• Pauses during eating to assess fullness.
• Separating liquids from meals if "overfull" feelings are common.

4. Hydration and Fiber: Go Gently

Hydration helps prevent constipation and supports overall health, but large volumes of fluid with meals can worsen fullness. Similarly, fiber is valuable for cardiometabolic health and the gut microbiome, but increases should be gradual to avoid bloating or cramping.^17,18 A dietitian can help titrate fiber from foods such as oats, beans, fruits, and vegetables to the individual's tolerance.

5. Monitor Alcohol, Sweets, and Ultra-Processed Foods

Some people on GLP-1 therapy may find that alcohol or high-fat, highly processed foods worsen GI side effects. Others may find that, because overall intake is lower, highly refined foods displace more nutritious options. Dietitians can help clients set realistic boundaries that still feel flexible and enjoyable.

Weight Regain, Plateaus, and Life After GLP-1

Studies show that when GLP-1 medications are stopped, a portion of the weight that was lost is often regained over the following months, especially if nutrition and lifestyle strategies do not change or if underlying drivers of weight gain are not addressed.^5,8

This is not a sign of "failure" or lack of willpower. Obesity is a chronic, relapsing condition influenced by genetics, hormones, environment, and social factors. Medication can powerfully shift those systems while it is being used, but long-term outcomes depend heavily on what happens around and after therapy.

Ongoing work with a registered dietitian can help individuals:

• Plan for potential plateaus and adjust habits gradually.
• Build enjoyable movement routines that are realistic over time.
• Develop skills for navigating holidays, travel, stress, and social events.
• Transition off medication (if and when appropriate) with strategies to support weight stability and health.

How Dietitians of America Supports People Considering GLP-1

DietitiansofAmerica.com is designed to help you find qualified nutrition professionals who understand not only food and health, but also the realities of modern obesity and diabetes care, including GLP-1 therapy.

Through the directory, you can:

• Search for registered dietitians with experience in weight management, diabetes, and cardiometabolic health.
• Filter by state, specialty, virtual vs in-person care, and areas of interest (for example, bariatric nutrition, PCOS, or GI health).
• Connect with professionals who collaborate with physicians, endocrinologists, and obesity medicine specialists.

If you are currently on a GLP-1 medication—or considering starting one—working with a dietitian can help you:

• Make the most of the medication's benefits.
• Reduce the risk of side effects where possible.
• Protect your long-term health, including muscle mass, bone health, and mental well-being.

Use the Dietitians of America directory to find a credentialed expert who can offer personalized, evidence-based support tailored to your medical history, goals, and everyday life.

Important: This article is for general education only and is not a substitute for medical advice, diagnosis, or treatment. Always speak with your healthcare provider before starting, changing, or stopping any medication, including GLP-1 therapies.

References

1. Collins L, Costello RA. Glucagon-Like Peptide-1 Receptor Agonists. StatPearls [Internet]. Updated 2024. National Center for Biotechnology Information.
2. Tran-Duc PN, et al. Cardiovascular benefits of glucagon-like peptide-1 receptor agonists in type 2 diabetes. Chinese Medical Science Journal. 2025.
3. Michos ED, et al. Role of GLP-1 receptor agonists in cardio-metabolic therapy: beyond glycemic control. Journal of the American Heart Association. 2023.
4. Zheng Z, et al. Glucagon-like peptide-1 receptor: mechanisms and emerging dual and triple agonists. Signal Transduction and Targeted Therapy. 2024.
5. Mozaffarian D, et al. Nutritional priorities to support GLP-1 therapy for obesity. American Journal of Clinical Nutrition. 2025.
6. Odigwe C, et al. Emerging role of GLP-1 agonists in cardio-metabolic therapy. Metabolism: Open. 2025.
7. World Health Organization. WHO guideline on pharmacological treatment of obesity in adults. 2025 press communication on GLP-1 therapies for obesity.
8. Gigliotti L, et al. Managing the gastrointestinal side effects of GLP-1 receptor agonists in obesity: recommendations for clinical practice. Postgraduate Medicine. 2022.
9. Fitch A, et al. Application of nutrition interventions with GLP-1 based therapies for obesity management. Obesity Medicine. 2025.
10. Therapeutic Goods Administration, Australia. Safety update on GLP-1 and related incretin drugs including Ozempic, Wegovy, Saxenda, Trulicity and Mounjaro, with mental-health and contraception warnings. 2025.
11. Gupta N, et al. Beyond blood sugar: a scoping review of GLP-1 receptor agonists and systemic outcomes. Frontiers in Endocrinology. 2025.
12. Spreckley M, et al. Bridging the nutrition guidance gap for GLP-1 receptor agonist care. International Journal of Obesity. 2025.
13. Application of nutrition interventions with GLP-1 based therapies in obesity management. Obesity Medicine. 2025.
14. Odigwe C, et al. Incretin-based therapies and lifestyle interventions: integrating nutrition into obesity pharmacotherapy pathways. Journal of the Academy of Nutrition and Dietetics. 2025.
15. NutritionEd.org. What is GLP-1 Nutrition Counseling? 2025 overview of dietitian-led support for GLP-1 patients.
16. Academy of Nutrition and Dietetics. Obesity Medications and the Role of RDNs in Comprehensive Care. EatRightPro.org clinical practice resources.
17. Harvard Health Publishing. How and why to fit more fiber and fermented food into your meals. 2024.
18. Aziz T, et al. Elucidating the role of diet in maintaining gut health to reduce disease risk. Nutrients. 2024.