An endocrinologist’s new weight-care system halted population-level weight gain and could reshape obesity treatment across America.
For years, endocrinologist Leigh Perreault, MD, believed there had to be a more effective way to help people manage their weight than simply advising them to eat healthier and exercise more.
“There was a moment I put my face in my hands and thought, ‘What am I doing?’ I would write a lot of prescriptions for patients’ diabetes, their blood pressure, their lipids and all these other conditions,” says Perreault, a professor of endocrinology, metabolism and diabetes at the University of Colorado Anschutz School of Medicine who practices in Westminster alongside primary care physicians.
“None of these people want to be on these medications, and I thought if I could just help them with their weight, many of these health concerns would probably go away,” she continues.
That realization led to the creation of a new system that is rapidly gaining attention in the field of obesity treatment.
Perreault and her colleagues developed PATHWEIGH, a structured process that helps primary care teams and patients make weight management a priority through dedicated clinic visits focused specifically on weight-related care. With support from the National Institutes of Health (NIH), the program was introduced in 56 UCHealth primary care clinics across Colorado to evaluate its impact. The effort ultimately reached 274,182 patients, making it one of the largest randomized trials ever conducted.
Research published in Nature Medicine found that PATHWEIGH reduced population weight gain by 0.58 kg over 18 months and shifted the overall trend from weight gain to weight loss, an important outcome from a public health perspective.
The program also increased the chances that patients would receive weight-related care by 23%.
“With PATHWEIGH, we showed that we absolutely eliminated population weight gain across all of our primary care, which has never been done previously,” Perreault says.
As a result, obesity specialists are increasingly viewing PATHWEIGH as a model for standard care, and several health systems around the country are exploring adoption of the program.
Creating a Clear Path to Weight Care
According to Perreault, one of PATHWEIGH’s biggest strengths is that it helps patients and primary care providers work toward the same goal.
“If you think about weight loss medicine or surgery or a weight loss program, those are all vehicles to weight loss,” Perreault says. “We built a highway that we could put all the vehicles on, so there’s actually a process for people to receive weight-related care if they wanted it.”
The process begins with signs placed in clinics informing patients that they can schedule a visit specifically focused on weight management simply by requesting one at the front desk.
Once a patient makes that request, a feature within the electronic health record automatically sends a survey. After the survey is completed, the information is incorporated directly into the provider’s notes. This allows appointments to focus less on collecting background information and more on discussing potential solutions.
“It made the whole process really efficient, and then effectively turned our note template into a menu of anything that we might do,” Perreault says. “It really made it extremely time efficient and consolidated everything we might do for a patient into one interface.”
Better Access to Obesity Treatment
Data gathered during the 18-month study showed that roughly one in four eligible patients received some form of weight-related care at least once. Most often, that involved guidance on lifestyle changes, but prescriptions for anti-obesity medications doubled during the intervention.
Unlike many traditional weight-loss programs, PATHWEIGH allows treatment plans to be tailored to each patient’s needs. It also reduces much of the discomfort that can make conversations about weight difficult for both patients and clinicians.
“Most people who want or need weight-related care never get it. Either they don’t ask for it, or the providers don’t bring it up, and if they do, the patient usually gets told to go home and eat less and exercise more, and then nothing happens,” Perreault says.
“The person gets frustrated, and they learn to not ask for help anymore, because it’s kind of embarrassing and it doesn’t help. This was a safe space to say, ‘Hey, if you would like medical assistance with your weight, we actually have a process for you to receive that now.'”
Population Weight Gain Reversed
Researchers note that rising obesity rates have been linked to an average population weight increase of about .5kg per year. Preventing that gain and turning it into weight loss could play a significant role in slowing the obesity epidemic.
“While it’s not a significant difference on an individual patient level, it’s a huge deal on a population and public health level,” Perreault says.
The researchers also found that patients who received measurable weight-related care through PATHWEIGH experienced greater weight loss. Even among those who did not receive identifiable weight-related treatment, the program helped reduce the amount of weight gain that would normally be expected.
Additionally, “when patients did receive discernible weight-related care, PATHWEIGH was associated with greater weight loss and also mitigated the expected weight gain for those who did not receive discernible weight-related care,” researchers concluded.
Expanding Beyond Colorado
Perreault says the program’s success has opened the door for broader adoption. Efforts are now underway to bring PATHWEIGH to health systems outside Colorado.
The Obesity Association, which is currently developing its first standards of care for obesity treatment, is highlighting PATHWEIGH as a recommended care process.
Five health systems spanning seven states are also considering the program as its creators work toward licensing the model.
“I’m really proud that PATHWEIGH was home-grown and built and tested here in Colorado,” Perreault says. “This is the blueprint that moves us forward.”
Reference: “Implementation and effectiveness of a care process to prioritize weight management in primary care: a stepped-wedge cluster-randomized trial” by Leigh Perreault, Qing Pan, Carlos Rodriguez, R. Mark Gritz, Peter C. Smith, E. Seth Kramer, Lauren Tolle, Lauri Connelly, Caroline Tietbohl, Johnny Williams II and Jodi Summers Holtrop, 11 December 2025, Nature Medicine.
DOI: 10.1038/s41591-025-04051-5
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