Unlocking Success in Obesity Trials: The Critical Role of Patient Engagement and Behavioral Science
As global obesity rates more than doubled between 1990 and 2022, continuing to pose a major public health challenge, the pharmaceutical industry has increasingly invested in the development of innovative weight loss treatments.[1] But despite the clinical promise of GLP-1 agonists and other emerging therapies, sponsors face an underappreciated challenge: engaging and retaining participants in obesity trials.
Obesity trials are uniquely complex. Participants often bring a history of unsuccessful weight loss attempts, emotional fatigue, and skepticism. These trials frequently require long study durations, intensive lifestyle interventions, and frequent site visits. These are all factors that contribute to high screen failure and dropout rates.
Less than half of individuals with obesity who express initial interest in a trial will ultimately enroll. And of those who do enroll, attrition rates can reach 30% or higher.[2,3,4]
Another key driver of retention challenges is the growing accessibility of weight loss medications. Especially in the United States, patients can go to a telehealth provider or their primary care provider and receive a prescription for weight loss medication. When participants can easily access effective treatments outside the trial—especially through telehealth or primary care— study retention becomes particularly difficult in placebo arms and post-treatment phases. This is reflected in dropout rates, which range from 25–40% in obesity trials, with higher attrition observed in placebo groups.[3,4,5] In CRO Consulting’s experience, attrition rates have even exceeded 40%.
Behavioral Science: An Untapped Asset
Traditional trial designs often overlook behavioral psychology. Yet behavioral science may hold the key to addressing many pain points in obesity research: motivation, habit formation, accountability, and emotional resilience.[2,6]
By embedding behavioral insights into protocol design, sponsors can:
Tailor messaging to match participants' motivations (e.g., health, appearance, family)
Use digital tools that track progress and deliver personalized nudges (like custom thank-you cards or AI software reminders)
Design visits and interventions that maintain engagement without causing burnout
Sponsors who treat participants as collaborators rather than subjects often see improved adherence and richer data. When participants understand the value of their contribution, they may be more likely to remain in the study.
Technology Meets Empathy
Wearable devices, mobile apps, and remote monitoring platforms can extend the reach of study teams and offer real-time support. But technology must be paired with empathy.
Check-ins should feel like care—not compliance.
Sites and CROs can play a pivotal role by training staff in motivational interviewing, addressing stigma, and creating a safe, encouraging environment for participants.
Obesity disproportionately affects communities that are historically underrepresented in clinical research. Thoughtful engagement strategies—such as offering transportation or childcare support, and building trust over time—can foster more equitable participation and ensure that weight loss treatments are studied in the populations that need them most.
Final Thoughts
As the next generation of weight loss medications moves through the pipeline, trial success will depend on more than efficacy endpoints. It will hinge on our ability to support, engage, and empower participants throughout the study journey.
At CRO Consulting Inc., we work with sponsors to integrate behavioral science, patient-centricity, and operational agility into every phase of obesity trial planning. Because when participants succeed, trials do too.
References
World Health Organization. Obesity and Overweight. World Health Organization. Published May 7, 2025. https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
Moe Alsumidaie. Behavioral Science: The Untapped Asset in Obesity Trial Strategy. The Clinical Trial Vanguard. Published June 4, 2025. Accessed July 26, 2025. https://www.clinicaltrialvanguard.com/analysis/behavioral-science-the-untapped-asset-in-obesity-trial-strategy/
Hedin L, Hagströmer M, Marcus C, Danielsson P. Process Evaluation of a Randomized Controlled Trial With a Mobile Health Intervention for Children With Obesity. Sage Open Pediatrics. 2025;12. doi:10.1177/30502225251348292
Siegel RM, Kist C, Kirk S, Kharofa R, Stackpole K, Sammons A, Dynan L, McGrady ME, Seo J, Urbina E, et al. A Randomized Controlled Trial Comparing Loss versus Gain Incentives to Improve Adherence to an Obesity Treatment Intervention in Adolescents. Nutrients. 2024; 16(19):3363. https://doi.org/10.3390/nu16193363
Festi D, Colecchia A, Sacco T, Bondi M, Roda E, Marchesini G. Hepatic steatosis in obese patients: clinical aspects and prognostic significance. Obesity Reviews. 2004;5(1):27-42. doi:https://doi.org/10.1111/j.1467-789x.2004.00126.x
Gillies K, Brehaut J, Coffey T, et al. How can behavioural science help us design better trials?. Trials. 2021;22(1):882. Published 2021 Dec 4. doi:10.1186/s13063-021-05853-x
