Study Identifies Which Patients With Obesity Respond Best to GLP-1-Based Treatment

Key Takeaways: 

• A Mayo Clinic study has identified a distinct biological subtype of obesity – a form of the “hungry gut” phenotype – that responds especially well to tirzepatide.
  
• People in this subgroup lost an average of 21.5% of their body weight after six months on tirzepatide, roughly double the 11.7% seen in other subtypes.
  
• The lower appetite-hormone levels traced back to reduced hormone production in the intestine rather than differences in the gut microbiome.
  
  
  

A step towards precision medicine for obesity

Why do some people lose a substantial amount of weight on GLP-1-based medications while others see far more modest results? A new Mayo Clinic study offers a potential answer, 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. The finding moves the field a step closer to precision medicine for obesity, where treatment is matched to an individual’s underlying biology rather than applied uniformly.

The research, published in the journal Gastroenterology, points to a future in which clinicians could predict, rather than simply hope, that a given therapy will work for a given person.

What the researchers found

The team studied 483 adults living with obesity and identified three distinct biological types of the disease. About one in four participants produced lower levels of GLP-1 and other hormones that help people feel full after eating.

This subgroup saw markedly better results on treatment. Patients in this group lost an average of 21.5% of their body weight after six months of tirzepatide, compared with 11.7% for patients in the other groups – losing nearly twice as much weight over the same period.

“Obesity is a complex disease driven by different biological mechanisms,” says senior author Andres Acosta, M.D., Ph.D., a gastroenterologist and the Delaney Family Director of the Nutrition Obesity Research Program 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.”

Understanding the “hungry gut” subtype

The subgroup that responded so strongly to tirzepatide shares a recognisable biological signature: people in this group produce lower levels of natural appetite-regulating hormones, experience faster stomach emptying and report greater hunger after meals.

Researchers describe this as a form of the “hungry gut” obesity phenotype, which is characterised by an abnormal duration of fullness. Rather than eating unusually large amounts at any one sitting, people with hungry-gut obesity may eat normal portion sizes but find themselves snacking more frequently, because the sense of fullness does not last as long as it should.

Because tirzepatide acts on the same appetite pathways that are underactive in this group, it appears especially well suited to addressing the biology that drives their eating patterns.

Why the underlying biology matters

The study also sheds light on why hormone levels differ in this subgroup. The researchers found that the reduced hormone levels were associated with decreased hormone production in the intestine itself, rather than with differences in the gut microbiome. That distinction offers new insight into the biology underlying this subtype and helps explain where the difference in treatment response originates.

Identifying the right therapy sooner could carry significant long-term benefits. Because obesity increases the risk of diabetes, heart disease, certain cancers and many other serious chronic conditions, matching people to the treatment most likely to help them – rather than relying on a one-size-fits-all approach – could improve long-term health outcomes.

What this means for clinical practice

The findings support growing efforts to personalise obesity treatment based on an individual’s biology. For clinicians, interpreting studies like this one increasingly depends on a firm grasp of how GLP-1-based medications act on appetite hormones and gastric emptying in the first place – the kind of grounding offered by CPD courses such as the College of Contemporary Health’s GLP-1RAs in Focus, which examines why some people respond more strongly to these treatments than others. Still, the authors are careful to note the limits of the current work. They caution that prospective studies are needed before this approach can be incorporated into routine clinical practice.

Even so, the results represent an important step towards more precise, individualised treatment for obesity – and towards a future in which people are guided to the therapy most likely to work for them from the outset.

Studies like this one land almost weekly, and making sense of them starts with understanding how GLP-1 receptor agonists actually work – from gut hormones and appetite regulation to why some people respond far more strongly than others. CCH’s GLP-1RAs in Focus – Why Drugs Like Ozempic Work is a two-hour, CPD-accredited online course created by Prof. Mike Bewick and Nigel Hinchliffe that builds exactly this foundation, whether or not you prescribe. Explore the course and interpret the next headline with confidence.

Source: Mayo Clinic