Research identifies a subtype of the ‘hungry gut’ obesity phenotype

Why do some people lose substantial weight with GLP-1-based medications while others see more modest results? A Mayo Clinic study offers a potential answer by identifying a distinct biological subtype of obesity that responds especially well to tirzepatide, a medication that mimics two naturally occurring hormones involved in appetite and blood sugar regulation, moving the field closer to precision medicine for obesity.

The research, published in Gastroenterology, identified a subgroup of patients with obesity who produce lower levels of natural appetite-regulating hormones, experience faster stomach emptying and report greater hunger after meals. This is a subtype of the “hungry gut” obesity phenotype, characterised by an abnormal duration of fullness. People with hungry-gut obesity may eat normal portion sizes but snack more frequently. 

These patients lost nearly twice as much weight after six months of tirzepatide treatment as patients with other obesity subtypes. 

“Obesity is a complex disease driven by different biological mechanisms,” says senior author Andres Acosta, M.D., PhD, a gastroenterologist and obesity researcher at Mayo Clinic in Minnesota. “Our findings suggest we can begin identifying which patients are most likely to respond to specific therapies rather than treating obesity as a single disease.”

Researchers studied 483 adults with obesity and found three different biological types of the disease. About 1 in 4 participants produced lower levels of GLP-1 and other hormones that help people feel full after eating. Patients in this group lost an average of 21.5% of their body weight after six months of treatment with tirzepatide, compared with 11.7% for patients in the other groups.

The findings support growing efforts to personalise obesity treatment using an individual’s underlying biology rather than relying on a one-size-fits-all approach. Because obesity increases the risk of diabetes, heart disease, certain cancers and many other serious chronic conditions, identifying the right therapy sooner could improve long-term health outcomes.

The researchers also found that the reduced hormone levels were associated with decreased hormone production in the intestine rather than differences in the gut microbiome, providing new insight into the biology underlying this subtype of obesity.

The authors caution that prospective studies are needed before this approach can be incorporated into routine clinical practice, but these findings represent an important step toward more precise, individualised treatment for obesity.