A novel weight management initiative called PATHWEIGH, developed by endocrinologist Leigh Perreault, has successfully stopped population-level weight gain in primary care settings across Colorado. Tested in a large-scale trial involving over 274,000 patients, the program increased access to obesity treatments and is now attracting interest from health systems nationwide. Published results show a 0.58 kg reduction in average weight gain over 18 months, marking a significant public health advancement.
Endocrinologist Leigh Perreault, a professor at the University of Colorado Anschutz School of Medicine who practices in Westminster, grew frustrated with standard weight management advice in primary care. Patients often left with generic recommendations to eat better and exercise more, despite ongoing issues like diabetes and hypertension. Perreault realized many medications treated symptoms rather than addressing obesity as the root cause. "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 said.
To tackle this, Perreault and colleagues created PATHWEIGH, a structured system funded by the National Institutes of Health. It rolled out across 56 UCHealth primary care clinics in Colorado, involving 274,182 patients in one of the largest randomized trials of its kind. The program features dedicated visits focused solely on weight care, triggered by patient requests at the front desk. This activates an electronic health record workflow, including a patient survey that streamlines clinician notes and emphasizes practical steps.
Results, published in Nature Medicine in 2025, revealed PATHWEIGH reduced average population weight gain by 0.58 kg over 18 months, reversing the typical upward trend. It boosted the likelihood of receiving weight-related care by 23%, with one in four eligible patients accessing services like lifestyle counseling. Prescriptions for anti-obesity medications doubled during the trial. "With PATHWEIGH, we showed that we absolutely eliminated population weight gain across all of our primary care, which has never been done previously," Perreault noted.
The approach customizes treatments, reduces awkward weight discussions, and builds a clear pathway for care, likened by Perreault to a "highway" for various weight loss options. While individual changes may seem modest, they hold substantial public health value against annual average gains of about 0.5 kg. The Obesity Association now recommends PATHWEIGH in its standards, and five health systems in seven states are exploring adoption. Perreault calls it a "home-grown" blueprint for advancing obesity care.
