GNC clinical research reveals critical nutritional gaps among GLP-1 users

Researchers from US retailer GNC reveal that people on GLP-1 medications have poor diet quality, consume insufficient protein per body weight, and are deficient in fiber, calcium, iron, magnesium, potassium, choline, and vitamins A, C, D, and E.

GNC states that its findings can help shape clinical practice guidance, supplement formulations, and education efforts to support the drugs’ long-term success. 

The authors note their study is the “first-ever real-world nutrition analysis of GLP-1 users,” which confirms earlier findings that people on these medications decrease food intake. 

“We set out last year to develop a product tailored to the unique needs of GLP-1 users,” says Brittany Johnson, Ph.D., registered dietitian nutritionist, senior manager of Scientific Affairs at GNC, and the study’s principal investigator. 

“However, we quickly realized there wasn’t enough evidence to inform a formula based on our scientific standards. That’s why our team decided to start at the foundation and understand exactly what nutritional inadequacies exist in this population.”

Nutrient deficiencies

The study, published in Frontiers, included 69 participants taking GLP-1 receptor agonist medications for at least one month. They answered online survey questions and completed a three-day food record, which the researchers used to calculate nutrient intakes compared to daily recommended intake levels. 

The participants consumed sufficient B vitamins, copper, phosphorus, selenium, and zinc compared to these reference values. 

However, they did not meet the daily recommended servings for fruit, vegetables, grains, or dairy, as specified in the US Department of Agriculture’s MyPlate daily recommendations for these food groups. When considering grams per kg/day, protein intake was significantly under daily needs. 

The research finds that GLP-1 users consume insufficient protein per body weight, and are deficient in fiber and several micronutrients.Participants consumed an average of 14.9 g of fiber, under recommended levels. 

Moreover, they consumed insufficient minerals (calcium, iron, magnesium, and potassium), vitamins (A, C, D, and E), and choline. They also overconsumed calories from fat (39.9%) and saturated fat (26 g).

Patient-centered nutritional guidance

Rachel Jones, registered dietitian nutritionist and EVP chief merchandising and science officer at GNC, says there was a lack of clinical nutritional research among GLP-1 users. The company aimed to examine GLP-1 users’ real-world dietary intake and habits to understand their nutritional needs.

“The results of our study provide critical evidence to guide the next generation of support for the growing population of GLP-1 users — whether through education, clinical nutrition advice, or dietary supplements,” adds Jones. 

Nutritional deficits from lowered food intake is a common consequence of these rapid weight loss medications, underscoring the importance of dietary quality. To support patients, medical experts recommend that clinicians identify pre-existing nutritional risk factors before treatment and advise patients on sufficient protein, fiber, micronutrients, and fluid intake. 

Earlier this month, four US organizations released eight nutritional priorities to support GLP-1 weight loss therapy. These priorities combine patient-centered support and nutrition with other lifestyle changes around activity, sleep, and mental stress. 

Several companies have launched GLP-1 support programs. For example, GNC selected products to help semaglutide users manage common side effects and challenges. Meanwhile, healthcare fintech provider NationsBenefits supports patients in maintaining muscle mass, nutrition, and hydration through nutrition counseling, meal planning tools, and grocery guidance.