A Dietitian’s Take on GLP-1 Injections

By Nicole Randazzo, MA, RDN, CDCES

With the rise of weight loss injections, there’s a lot of discussion and even confusion. As a dietitian working in the weight loss and diabetes space, I want to share a balanced perspective on what these medications can (and can’t) do.

GLP-1s: Not New, Just Repurposed

GLP-1 receptor agonists aren’t new — they’ve been used for over 15 years to manage type 2 diabetes. Since weight loss was a consistent secondary benefit, the pharmaceutical industry developed a version specifically for obesity management. In 2021, semaglutide (Wegovy) became the first GLP-1 approved solely for weight loss. Soon after, tirzepatide (Zepbound) was introduced and showed even greater results, with clinical trials demonstrating nearly double the weight loss benefits compared to Wegovy (Jastreboff et al. 2022).

The Benefits — and the Challenges

💡 On their own, GLP-1s typically help people lose about 10–12% of their body weight (“Once-Weekly Semaglutide”). For someone at 200 lbs, that’s around 20–24 lbs. While this is significant, it may not always be enough to reduce long-term risk for chronic conditions or fully protect metabolic health.

Zepbound, in particular, can yield nearly double that amount of weight loss due to its stronger effects on satiety (Jastreboff et al. 2022). While this is a positive outcome for many, it can also present challenges: when you’re rarely hungry, it’s easy to under-eat or miss out on key nutrients your body needs. Over time, this can contribute to slowed metabolic rate, loss of muscle mass, or difficulty sustaining results.

Common Side Effects of GLP-1s

Like any medication, GLP-1 receptor agonists come with potential side effects. The most frequently reported include:

Nausea
Vomiting
Diarrhea
Constipation
Abdominal pain or bloating
Decreased appetite
Indigestion

For many, these symptoms improve over time as the body adjusts, but for others, they can interfere with adequate nutrition and quality of life.

Black Box Warning

All GLP-1 receptor agonists, including semaglutide and tirzepatide, carry an FDA black box warning for thyroid C-cell tumors. While this risk has been observed in rodent studies, it has not yet been confirmed in humans. Still, the warning is important, and these medications are not recommended for individuals with a personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN 2) (“FDA Label for Wegovy”).

Why Nutrition Counseling Matters

This is where nutrition counseling plays a crucial role. Without proper guidance, individuals may unintentionally under-nourish themselves, stall progress, or struggle to maintain results once medication use changes.

As a dietitian, my role is to help clients:

Protect metabolism and muscle mass
Build sustainable eating habits that fit into their lifestyle
Learn how to nourish the body even when appetite is suppressed
Develop long-term strategies to maintain weight loss whether staying on the medication or eventually stopping

It’s also important to note that with treatment cessation, weight regain is common. One study found that patients treated with Wegovy regained an average of 11.6% of their weight after discontinuation (Palana et al.). Sustainable nutrition and lifestyle support are what help prevent this rebound.

Final Thoughts

GLP-1 injections can be powerful tools for weight management, but they are not a complete solution on their own. A combination of medical treatment, nutrition counseling, and lifestyle changes offers the best chance for long-term success.

👉 If you’d like support in navigating this process, I’m currently accepting new clients and am in-network with major private insurances. Book a discovery call through the link in my bio to learn more about how I can support you.

Works Cited

“FDA Label for Wegovy (Semaglutide).” U.S. Food and Drug Administration, 2021, http://www.accessdata.fda.gov/drugsatfda_docs/label/2021/215256s000lbl.pdf.
Jastreboff, Ania M., et al. “Tirzepatide Once Weekly for the Treatment of Obesity.” New England Journal of Medicine, vol. 387, no. 3, 2022, pp. 205–216. doi:10.1056/NEJMoa2206038.
“Once-Weekly Semaglutide in Adults with Overweight or Obesity.” New England Journal of Medicine, vol. 384, no. 11, 2021, pp. 989–1002. doi:10.1056/NEJMoa2032183.
Palana, Cesar, et al. “Analyzing the Effects of Semaglutide (Ozempic/Wegovy) on Metabolism: Investigating Correlations with Weight Reduction.” Cureus, vol. 16, no. 5, 2024, doi:10.7759/cureus.63727.