Jennifer Lynn-Pullman had been taking Wegovy for a few months when she began shivering during a walk on a hot August day.
"It was about 85 degrees – I should have been sweating," said Lynn-Pullman, a 48-year-old dietitian from Pennsylvania.
A weeklong food log revealed she was eating less than 900 calories a day – well below the 2,000 daily calories recommended by the US Department of Agriculture for a moderately active woman in her 40s and below the 1,200-1,500 calories commonly advised for women on weight loss drugs.
Since starting the weekly injections, she'd been losing a pound or two a week – which she considered reasonable. Yet she'd fallen into a dangerous trap experts warn could become more common as GLP-1 weight loss drugs become more widely used: She wasn't eating enough calories.
Lynn-Pullman, also a certified obesity and weight management specialist, upped her calorie intake and added more protein. Within a week, she felt better – no more chills.
Because of her professional background, she was able to spot and address her symptoms quickly. But her experience raises crucial questions: If this can happen to a nutrition expert, what about someone without her expertise? Could they miss early symptoms, and would the health fallout be worse?
GLP-1s and the Risk of Malnutrition
The class of obesity medications known as GLP-1 agonists – also approved to treat type 2 diabetes and to lower the risk of heart and blood vessel problems in some adults with heart disease – is highly effective for weight loss. The drugs, which include semaglutide (Ozempic, Rybelsus, Wegovy) and tirzepatide (Mounjaro, Zepbound), work by mimicking the body's natural GLP-1 hormone. They act on brain receptors to slow digestion, increase feelings of fullness, and reduce appetite.
But doctors have growing concerns: Some patients on GLP-1s unintentionally eat too little and become malnourished. A new study in Obesity Reviews supports these worries, finding that many patients don't get enough nutritional guidance, leaving them vulnerable to deficiencies.
"We see cases where people take a GLP-1 medication and become so severely malnourished that they need to be hospitalized," said Rebecca Boswell, PhD, director of the Penn Medicine Princeton Center for Eating Disorders, in Philadelphia. "It's not uncommon."
Malnutrition can disrupt body temperature, blood sugar, blood pressure, and electrolytes and cause vitamin deficiencies. Some symptoms, such as fatigue and lightheadedness, overlap with GLP-1 side effects, so careful assessment is key. Health outcomes can range from muscle loss to a weakened immune system to poor wound healing, and in rare cases can be life threatening.
"These meds are incredible for treating diabetes," Boswell said. "Where my fear comes in is when they're indicated for weight loss."
GLP-1 doses for weight loss are higher than for diabetes, and research on the higher-dose effects is limited, especially in subpopulations such as people with eating disorders, Boswell said.
The Thinking Around 'Food Noise'
Lynn-Pullman, who has been on Wegovy since May 2023, said the drug helped her win a lifelong wrestling match with weight. After dropping 60 pounds and reaching her goal weight in 2024, she's remained on the medication, although she's planning to talk with her doctor about tapering her weekly dose.
Taking the medication also helped her recognize a common phenomenon among overeaters known as "food noise."
"I didn't really understand what people were talking about when they talked about food noise until I actually experienced the change myself," she said. "Prior to the GLP-1, I couldn't pass up a cookie or a piece of chocolate. The afternoons were always tough, and I'd need to find something to snack on."
Instead of "food noise," psychologists prefer to call thinking about food all the time "rumination," said Kerri Boutelle, PhD, director of the Center for Healthy Eating and Activity Research at the University of California, San Diego.
"Patients with bulimia or binge eating disorders will say, 'It is calling me,'" said Boutelle. "They can't get through their day without eating the cake that's in the refrigerator. They're ruminating, thinking about food, planning food."
Clinically, she said, "I've seen [GLP-1 drugs] change people's lives."
But what if a GLP-1's ability to turn off food noise does the job too well, as it did for Lynn-Pullman, who didn't realize she wasn't getting enough calories? Or worse, what if a patient intentionally misuses a GLP-1 to quiet that food chatter?
One case report published in the Journal of Clinical Psychopharmacology in 2024 describes a woman with a history of anorexia who intentionally took more of a GLP-1 medication than had been prescribed to lose weight. She ended up in the emergency room multiple times with malnutrition-related symptoms. Even when she was admitted to the hospital, she persistently refused to eat or to take supplemental nutrition.
Boswell said marketing from weight loss drug companies using the term "food noise" also concerns her, especially because of its influence on people with eating disorders. Abuse of diet pills and other diet aids is well-documented in medical literature, with some studies reporting prevalence rates in the 50% range.
"What we think about food noise, as eating disorder professionals, is hunger," said Boswell. "GLP-1s turn down the volume on hunger, and that's a really dangerous signal to give up on. We developed hunger and food-related reward processing to prevent starvation, evolutionarily speaking. So to turn away from hunger is to turn away from a really powerful signal of what your body needs nutritionally to function at its best."
She added, "GLP-1s make it very difficult, if not impossible, to engage in intuitive eating."
Too Little Screening, Too Easy to Get
While the world waits for science to unravel more information about the risks of malnutrition and other health issues linked to GLP-1s, millions of Americans are being prescribed the drugs, often outside close medical supervision. A May 2024 KFF national survey found that 1 in 8 U.S. adults had taken a GLP-1 drug. A more recent August 2025 RAND survey reported similar results: 11.8% of Americans have tried a GLP-1 drug for weight loss, including about one-fifth of women ages 50 to 64.
"One of the biggest problems I have seen is the ease with which patients can order these online – at a one-stop-shop brief telehealth evaluation – despite being at a normal or below normal weight, with no medical indication, and an active eating disorder," said Angela Guarda, MD, director of the Eating Disorders Program at Johns Hopkins Hospital in Baltimore.
Experts believe more stringent screening methods need to be in place before doctors prescribe them for weight loss. This could ensure early identification of patients at risk of malnutrition, misuse, or abuse of the drugs, as well as people with eating disorders.
The screening process could be similar to screening used for patients who want to have bariatric surgery, which includes assessment for eating disorders and other mental health conditions, said Boswell.
"Not just an initial assessment, but ongoing assessment. That isn't happening currently. I think it's something that's really missing from the clinical care around GLP-1s," she said.
Nutrition counseling, mental health support, and closer medical monitoring should be part of the treatment plan for anyone on a GLP-1 drug for weight loss, said Ellen A. Schur, MD, MS, an associate professor of medicine at the University of Washington School of Medicine in Seattle. But the cost of these support services may too high for many people.
What Lies Ahead?
Weeding through the impact of GLP-1s on the body will take time.
"I've been in weight management and eating disorders for 30-plus years, and weight management is not just about eating less and exercising more," Boutelle said. "That's what people think. It is not. It is so incredibly complicated and multifactorial – it's genetics, metabolism, whether or not you were breastfed, your environment, sleep plays a role."
Boswell said researchers need data "right from the start, to look at GLP-1 use, from the initial screening timepoint through their use and their continuation or discontinuation, to see how eating disorder symptoms and nutritional status change."
She'd like to better understand who is at risk of getting an eating disorder and malnutrition while on a GLP-1.
"Some people who don't yet have problems with eating can develop more significant problems through overuse of these medications," she said. "People who've lost weight on the medication and have received a lot of positive reinforcement can develop a hypervigilance around eating and social acceptance and appearance."
Boutelle is also interested in studies involving people who want to use a GLP-1 drug "to lose that 10 pounds that they can't get rid of, that 10 pounds that they gained during menopause," such as people who may still be in the so-called normal weight range based on BMI, but whose blood pressure, cholesterol, and/or blood sugar are inching up due to that extra weight.
Schur said there's a host of GLP-1 related psychological and behavioral studies that could be done, too.
"You could research psychological distress in people on GLP-1s versus people not on them," she said. You could compare actual overeating with perceived overeating on versus off the medication. "That might tell you what's happening in the brains of people on a GLP-1."
"I think we are just beginning to understand all the ways that we need to support people who are taking these medications," Boswell said.
