Preserving Nutrition During GLP-1 Treatment

The more people who use incretin therapies—including GLP-1 RAs and dual-receptor agonists—for weight loss, the more the medical community learns about them. These treatments work by suppressing appetite, delaying gastric emptying, and altering absorption.

Reducing caloric intake naturally raises questions about nutrition. Some mainstream headlines go so far as to sound the alarm on diseases like scurvy making a comeback. Let’s look at the facts about nutrition for patients using GLP-1s and other incretin therapies.

Why Patients Need Purposeful Plans For GLP-1 Nutrition

To begin this discussion, here are some weight loss medications that fall into this category, some of which are not GLP-1 RAs but work in much the same way.

• Semaglutide: A GLP-1 receptor agonist indicated for weight loss as Wegovy and available as an injection or pill
• Tirzepatide: An injectable GLP-1/GIP receptor agonist, indicated for weight loss as Zepbound
• Liraglutide: An injectable GLP-1 receptor agonist that goes by the brand name Saxenda
• Orforglipron: An oral non-peptide GLP-1 receptor agonist approved by the FDA in April 2026

Each of these is effective for weight loss, which can occur rapidly. The next generation of these medications in the pipeline promises even faster results.

The weight loss indications for these drugs typically state that they should be used in combination with diet and exercise. Delayed gastric emptying increases feelings of satiety, which is why these drugs help with weight loss. However, if a person feels too full too often, they may not eat enough nutrients. Further risks to nutrition include the side effects associated with incretin therapies. Among the most common are vomiting and diarrhea, which can adversely affect the body’s ability to absorb nutrients. Semaglutide has even been shown to alter taste perception, at least in rats. Robust human data remain limited.

Getting adequate calories from the right types of foods may require some education for the patient. Even when they understand how to track and reduce calories, they may do so in an unbalanced way.

Evidence-based nutritional and behavioral therapy can be employed to guide patients and help them to get adequate nutrition on GLP-1s and related drugs.

Nutrient Deficiency Symptoms to Watch During GLP-1 Treatment

Treatment may begin with baseline screening to review present dietary habits and knowledge, and to uncover emotional triggers or disordered eating. Based on the person’s existing habits, they may require more or less education and adjustment to achieve adequate nutrition during treatment.

A cross-sectional study published in Frontiers in Nutrition asked participants who had been using a GLP-1 for at least one month (N = 69) to answer questionnaires and complete a three-day food record. Participants overconsumed calories from fat and saturated fat. They did not meet the daily recommended MyPlate servings for fruit, vegetables, grains, or dairy, and their protein intake was significantly under daily needs. They also had insufficient intake of:

• Fiber
• Calcium
• Iron
• Magnesium
• Potassium
• Choline
• Vitamins A, C, D, and E

Reduced intake can lead to deficiencies. It may be helpful to advise a patient on incretin therapies about what to eat for the above nutrients. On return visits, signs of a deficiency may include:

• Fatigue
• Muscle pain or cramps
• Mood changes
• Dry skin
• Brittle hair or nails
• Light-headedness
• Excessive thirst
• Bleeding gums

This is not an exhaustive list, and many of these symptoms could signal many different conditions, related or unrelated to incretin therapy (more on this below). These medications do not require any specific labs, but if you have concerns about a patient’s nutrition, periodic testing may inform the recommendation of supplements.

How to Maximize Nutrient Intake with Lower Calorie Intake

A Joint Advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and the Obesity Society published their nutritional priorities for patients taking GLP-1s in the American Journal of Lifestyle Medicine. They appraised the scientific literature to identify and summarize relevant topics and emerging directions.

The authors acknowledge that GLP-1 nutrition, as such, is not yet a widespread idea. They advise that “​​nutritional and medical management of gastrointestinal side effects is critical, as is navigating altered dietary preferences and intakes, preventing nutrient deficiencies, preserving muscle and bone mass through resistance training and appropriate diet and complementary lifestyle interventions.”

Eating fewer calories while preserving nutrition means cutting back on empty calories first. Counsel patients on the importance of reducing refined starches and sugars, for example. If they don’t prioritize eating nutritional foods first, such as vitamin-dense vegetables, protein, and fiber, they may get full on empty calories. In other words, save dessert for dessert! When they fill up on the foods they need for good health, they may find they don’t even want the extras.

Preventing Muscle and Bone Loss with GLP-1 Nutrition Plans

Strong bones and muscles are integral to overall health and especially important for exercising, a key component of weight loss. A GLP-1 nutrition plan will place importance on bones and muscles.

Bone Health

Research has tied GLP-1 use to bone health risks. One study presented at the 2026 AAOS Annual Meeting tracked health outcomes for 73,483 adults taking GLP-1s over five years. The researchers compared them against a control group for rates of osteoporosis, gout, and osteomalacia.

In the GLP-1 users, they observed:

• 29% higher risk of an osteoporosis diagnosis
• 12% higher risk of a gout diagnosis
• A 2.55-fold higher risk of an osteomalacia diagnosis

Muscle Health

When weight alone is used as a metric of progress, it can mask a loss of muscle. Those with obesity may already be living with sarcopenia, or reduced muscle mass, especially if they are older.

People taking incretin medications should make a point of getting enough calories, including enough protein, to maintain or build muscle. Their exercise routine can work in tandem with diet to help minimize muscle loss. Protein intake recommendations vary, depending on age, renal function, and other individual needs, but in general range from 0.8-1.5g/kg with those on Incretin therapy often encouraged toward the higher end to preserve lean mass.

Focus on Protein Intake

Protein aids in satiety, preserves lean muscle mass, and can help achieve weight loss goals. However, eating less could lead someone to eat inadequate amounts of protein.

The lay media talks a lot about protein intake, but one cannot assume every patient understands how to get adequate protein. They can get it from meat, eggs, and dairy, as well as from various plant-based protein sources such as legumes, tofu, tempeh, seitan, and plant-based protein powders.

While there is limited research thus far, some patients taking GLP-1s report new food aversions. These often relate to meat or other high-protein foods, colloquially referred to as “meat ick.” Let patients know many food options provide protein. Working with a nutritionist may help them discover foods that fit their taste and lifestyle without compromising nutrition.

Fiber For GLP-1 Side-Effect Reduction

Fiber is important because it is associated with healthy gut bacteria, less inflammation, and weight loss. The daily recommended fiber intake is 25g for women and 38g for men. High-fiber sources include chia seeds, lentils, chickpeas, Brussels sprouts, oranges, and soybeans. Also, eating the skin of fruits and vegetables can add more fiber to one’s diet.

Not only is adequate fiber important for overall health, but it can also help address some of the digestive side effects of weight loss medications.

Preventing Vitamin Deficiencies

As mentioned above, vitamin deficiencies are among the nutritional challenges of taking GLP-1s. Typically, vitamin deficiencies can be marked by food cravings and increased hunger, but incretin therapy would negate these signs, so it’s important to watch for other ones. These are some of the specific vitamin deficiencies to watch out for and how to identify them.

Vitamin A

Vitamin A deficiency is extremely rare in the U.S., except in certain diseases like cirrhosis of the liver. However, this vitamin is important for vision, metabolism, and cell development. Someone deficient may have vision problems or dry, itchy skin.

B Vitamins

There are eight essential B vitamins (1, 2, 3, 5, 6, 7, 9, and 12), and each has its own role. For example, vitamin B6 is associated with reducing inflammation, while B12 helps the body produce red blood cells. Deficiency of these latter two vitamins may include fatigue, mood changes, or memory loss.

Vitamin C

Vitamin C is important for the immune system and to help the body absorb iron. A deficiency can cause fatigue or lead to scurvy, which is marked by bleeding gums, loose teeth, and bleeding under the skin.

Vitamin D

Vitamin D supports bone and muscle health by maintaining the balance of calcium in the body. Deficiencies are common in the U.S. and worldwide. Symptoms may include muscle weakness and bone pain.

Vitamin E

Vitamin E deficiencies are rare, but this vitamin is important for protecting cells from free radicals. Signs may include muscle weakness and fatigue.

Vitamin K

Vitamin K is involved with blood clotting, bone metabolism, and cardiovascular health. Deficiencies can be seen in newborns but are rare in adults. Signs may include easy bruising and bleeding gums.

Certain vitamins can reduce inflammation, which is important because obesity predisposes a person to pro-inflammatory states and oxidative stress.

Iron and Calcium Deficiencies

Other nutrients to monitor include iron and calcium.

Iron Deficiency

When the body doesn’t get enough iron, a lack of red blood cells can lead to anemia. Iron-deficient anemia is marked by pale skin, fatigue, weakness, shortness of breath, and lightheadedness.

Calcium Deficiency

Hypocalcemia occurs when the level of calcium in the blood gets too low. Symptoms include dry, scaly skin, muscle cramps, and brittle nails.

Dehydration Risks with GLP-1s

Decreased calorie intake may mean decreased fluid intake and, thus, the risk of dehydration. Adequate hydration is important for weight loss and can help reduce the risk of constipation, a common side effect of GLP-1s. Signs of dehydration include thirst, dry mouth, dizziness, and headache.

How Providers Can Collaborate with Dietitians

If you are treating a lot of patients using GLP-1s or other incretin therapies, it is a good idea to keep up with dietary knowledge and to build relationships with those with related professional expertise. Dietitians play an important role in the obesity management team. You might refer a patient to a registered dietitian to help them transition onto (or back off of) a weight loss medication, and to maintain good nutrition along the way.

This professional can design meal plans, recommend needed supplements, offer insights into managing side effects, and help the patient sustain long-term health changes.

Many insurance plans, including those on the Affordable Care Act marketplace, cover nutritional counseling by a dietitian or nutritionist as a preventative service. You might suggest that patients start by searching their insurer’s website for more information and the names of dietary professionals in their area (or available virtually).

One of the benefits of OMA membership is the ability to network across disciplines and specialties to support patients seeking to overcome obesity. You are part of a team that can empower patients to find the treatment that works for them and live their healthiest lives.