GLP-1s for Weight Loss: Nutrition Considerations
Written by Christy Walowit MS, RDN
GLP-1 medications are a class of drugs originally developed to support blood sugar regulation in people with type 2 diabetes. In recent years, they’ve gained widespread attention—both in the media and in clinical settings—after semaglutide (brand names: Wegovy, Ozempic) was FDA-approved for weight loss in 2021.
At As You Are Nutrition, we know that the decision to start a medication like this is deeply personal. That’s why we’re committed to supporting informed consent and honoring body autonomy. We believe you deserve access to clear, compassionate information—free from stigma or pressure—so you can make the choices that align best with your values, health needs, and lived experience.
This blog will cover some key factors to consider when evaluating the potential benefits and risks of GLP-1 medications for weight loss—specifically among individuals without a diabetes diagnosis. Whether you’re currently using these medications, considering them, or just curious, we’re here to provide context, clarity, and care.
Disclaimer: This content is for informational purposes only and is not intended to replace medical advice, diagnosis, or treatment. If you are struggling with an eating disorder or related health concerns, please consult a qualified healthcare professional, such as a doctor, therapist, or registered dietitian, for personalized guidance and support. If you need immediate help, reach out to a medical provider or a crisis support resource in your area.
What are Glucagon-like Peptide 1 Receptor Agonists (GLP-1s)?
GLP-1 receptor agonists are a class of medications that have been on the market for decades, originally developed for improving blood sugar control for adults living with type 2 diabetes. Semaglutide is a commonly prescribed type of GLP-1 receptor agonist medication. Semaglutide is sold as “Ozempic” for treating type 2 diabetes, and as “Wegovy” for weight loss, with Wegovy containing a higher dose. Many people use Ozempic “off-label” for weight loss, even if they don’t have diabetes. We will mostly be using the word “GLP-1” in this blog to refer to this class of drugs for simplicity’s sake!
While semaglutide (brand names: Wegovy, Ozempic) is a well-known GLP-1, it’s not the only one—and it’s not exactly the same as medications like Mounjaro or Trulicity. Several other medications fall under this category, each with its own unique formulation and characteristics:
Dulaglutide (brand name: Trulicity)
Liraglutide (brand names: Saxenda, Victoza)
Tirzepatide (brand names: Zepbound, Mounjaro) – Note: Tirzepatide also mimics another hormone called GIP (glucose-dependent insulinotropic polypeptide), which may enhance its effects.
Semaglutide oral tablet (brand name: Rybelsus) – This is the only GLP-1 medication currently available in pill form.
Most GLP-1s are taken as a once-weekly injection, but Rybelsus is a daily oral medication, taken on an empty stomach with water, at least 30 minutes before eating.
How do GLP-1 Medications Work?
GLP-1 is a naturally occurring hormone produced in the small intestine in response to eating. It plays several important roles in the body: it stimulates the pancreas to release insulin (which helps lower blood sugar), reduces the release of glucagon (which helps prevent blood sugar spikes), slows down gastric emptying (digestion), and signals the brain to promote feelings of fullness or satiety.
GLP-1 medications contain a synthetic or artificial version that mimics this hormone.
GLP-1 medications are often used to treat lower risk factors for cardiovascular disease (including insulin resistance, prediabetes, hypertension, and hyperlipidemia, etc.) that have not responded to other medications or interventions.
Fun Fact: this synthetic version of GLP-1 that is used in these medications was derived from venom found in gila monsters!
What are the Side Effects or Risks?
GI Symptoms:
Much of the initial weight loss from GLP-1s can be attributed to changes in GI symptoms, which can range from mild to severe depending on the person. Mild GI side effects often include nausea, vomiting, diarrhea, or constipation among others. Other rare, but severe side effects may include gastroparesis, kidney disease, ileus (bowel obstruction), and pancreatitis. These side effects can be unpleasant and disruptive, so it is very important to start with a low dose and allow your body time to adjust. Most GI symptoms associated with GLP-1s occur within the first 3 months of taking the drug.
Malabsorption:
The GI symptoms associated with GLP-1 use can also impact your body’s ability to absorb and utilize important nutrients. These nutrients include protein, iron, vitamin B12, folic acid, vitamin D, and calcium. It’s recommended to complete blood labs prior to starting a GLP-1 medication, with periodic follow-ups throughout its use, so that any deficiencies can be identified and corrected through dietary methods or supplementation.
GLP-1 medications can reduce gastric secretions, which in turn lowers stomach acid levels. This can lead to malabsorption, a condition where your body struggles to properly absorb nutrients from food. As a result, even if you’re eating a healthy, well-balanced diet, your body may not be able to fully utilize all the nutrients you’re consuming.
Malnutrition:
GI symptoms, low appetite, and malabsorption may increase the risk of malnutrition. Malnutrition is a serious condition that impacts every system in the body—impacting energy levels, immune function, muscle mass, bone health, and more. A registered dietitian can help you recognize early signs, adjust your intake to meet your body's needs, and create a nutrition plan that supports both symptom management and long-term health.
Other Risks:
Another important consideration when using GLP-1 medications is the potential risk of suicidal thoughts or behavior. Make sure to discuss your decision to start a GLP-1 with your mental health provider and other members of your healthcare team. GLP-1s are not recommended for people with a personal or family history of certain thyroid tumors or cancers, and their use is strongly discouraged among those with eating disorders.
Do GLP-1s Cause Rapid Weight Loss?
Dramatic weight loss is not realistic for the majority of individuals prescribed GLP-1s at appropriate, evidence-based doses. Unfortunately, expectations are often distorted by media hype and social media influencers whose experiences may not reflect typical outcomes. It’s important to approach this medication with realistic expectations and individualized goals.
Studies have found approximately 5-10% average weight loss when prescribed at the maximum dosage. There are studies for GLP-1 medications that potentially show greater weight loss, however this is typically in combination with caloric restriction and increased exercise that may be challenging to maintain long-term. Additionally, keep in mind there are multiple ways research data can be manipulated to show better outcomes than can realistically be expected by the general public.
At As You Are Nutrition, we take care to help clients avoid rapid or excessive weight loss, as this can increase the risk of muscle loss, malnutrition, and disordered eating behaviors. Our goal is to support safe, gradual, and sustainable changes that prioritize overall well-being—not just numbers on a scale. If you are using or considering a GLP-1 medication, your dietitian can work with you to monitor nutrition status, adjust intake as needed, and ensure your body is getting the nourishment it needs during the process.
The Bottom Line:
While GLP-1 medications can be a valuable tool for improving health and reducing cardiovascular risks, they are not a one-size-fits-all solution or a quick fix. Like any treatment, they come with their own set of risks and limitations. It's important to remember that weight loss—whether through medication or other means—does not automatically lead to better health, and weight cycling/rapid weight loss may carry its own set of health risks. Additionally, the benefits of GLP-1 medications for heart disease are evident regardless of any changes in weight. Your Registered Dietitian can help you evaluate the potential benefits and risks, make informed decisions about your body, and support you in reaching your long-term health and wellness goals.