Gia Merlo


Gia Merlo Headshot

Gia Merlo

Clinical Professor, Nursing & Psychiatry
Senior Advisor on Wellness

1 212 998 5323

433 First Ave
New York, NY 10010
United States

Gia Merlo's additional information

Gia Merlo, MD, MBA, Med, DipABLM, FACLM is a clinical professor of nursing and Senior Advisor on Wellness, a clinical professor of psychiatry at the NYU Grossman School of Medicine, and a fellow of the American College of Lifestyle Medicine. Merlo recently published a textbook Lifestyle Nursing (Taylor & Francis/CRC Press, August 2022) that expands Lifestyle Medicine (an evidence-based approach in preventing, treating, and oftentimes, reversing chronic diseases) to Nursing. Her first book, Principles of Medical Professionalism (Oxford University Press, 2021), stresses the importance of physician wellness, the need to address the social determinants of health, as well as the need to address chronic diseases with prevention. Merlo is the Associate Editor of the American Journal of Lifestyle Medicine. She is a contributing author of the American College of Lifestyle Medicine (ACLM) curriculum Lifestyle Medicine 101 and of the board review course, Foundations to Lifestyle Medicine.

Merlo's current book projects include Medical Professionalism: Theory, Education, and Practice (Oxford University Press, expected 2023), Lifestyle Psychiatry: Through the Lens of Behavioral Medicine (Taylor & Francis/CRC Press, expected 2023), A Handbook of Lifestyle Nursing (expected 2023).

Merlo is a part of the Psychiatry Faculty Group Practice at NYU Grossman School of Medicine and sees patients at NYULangone Health Psychiatry, 1 Park Avenue, New York, NY. She completed her Master of Education in Health Professions at Johns Hopkins University School of Education in August 2022 and is currently an Adjunct Faculty at Johns Hopkins helping students in the program complete their capstone projects.

Merlo has served on the board of directors of many nonprofits over the years and is currently on the board of directors of Plant-Powered Metro of New York (PPMNY) and the advisory board of the Global Positive Health Institute (GPHI). She is chair of the Mental and Behavioral Health Member Interest Group of the ACLM. She has been involved in clinician care and medical education for nearly 30 years in professional development and mental health, particularly for healthcare professionals. 

Before joining NYU, Merlo was an associate dean of health professions at Rice University. She also taught medical students, residents, and fellows at Baylor College of Medicine, where she was a 2017-19 Master Teacher Fellow. She has served on the faculty at the University of Pennsylvania School of Medicine, Baylor College of Medicine, Rice University, Texas Children’s Hospital, and Children’s Hospital of Philadelphia.


MD - Nagarjuna University
MBA - Temple University
MEd - John Hopkins University

Academy of Professionalism in Health Care
American Academy of Child and Adolescent Psychiatry
American College of Lifestyle Medicine
American Medical Association
American Psychiatric Association

Faculty Honors Awards

Master Teacher Fellowship, Baylor College of Medicine (2019)
Houston’s 50 Most Influential Women, Houston Women’s Magazine (2018)
Favorite Professor Award, Rice University Scholar Athletes (2017)
Fellowship, American Psychoanalytic Association (1997)


Gut microbiota, nutrition, and mental health

Merlo, G., Bachtel, G., & Sugden, S. G. (2024). Frontiers in Nutrition, 11. 10.3389/fnut.2024.1337889
The human brain remains one of the greatest challenges for modern medicine, yet it is one of the most integral and sometimes overlooked aspects of medicine. The human brain consists of roughly 100 billion neurons, 100 trillion neuronal connections and consumes about 20–25% of the body’s energy. Emerging evidence highlights that insufficient or inadequate nutrition is linked to an increased risk of brain health, mental health, and psychological functioning compromise. A core component of this relationship includes the intricate dynamics of the brain-gut-microbiota (BGM) system, which is a progressively recognized factor in the sphere of mental/brain health. The bidirectional relationship between the brain, gut, and gut microbiota along the BGM system not only affects nutrient absorption and utilization, but also it exerts substantial influence on cognitive processes, mood regulation, neuroplasticity, and other indices of mental/brain health. Neuroplasticity is the brain’s capacity for adaptation and neural regeneration in response to stimuli. Understanding neuroplasticity and considering interventions that enhance the remarkable ability of the brain to change through experience constitutes a burgeoning area of research that has substantial potential for improving well-being, resilience, and overall brain health through optimal nutrition and lifestyle interventions. The nexus of lifestyle interventions and both academic and clinical perspectives of nutritional neuroscience emerges as a potent tool to enhance patient outcomes, proactively mitigate mental/brain health challenges, and improve the management and treatment of existing mental/brain health conditions by championing health-promoting dietary patterns, rectifying nutritional deficiencies, and seamlessly integrating nutrition-centered strategies into clinical care.

Bipolar Disorders

Sugden, S. G., Merlo, G., & Bachtel, G. (2023). In Lifestyle Psychiatry (1–, pp. 331-341). CRC Press. 10.1201/b22810-32
Bipolar Disorder (BD) is a chronic mental health disorder that has a worldwide prevalence rate between 1.5 and 5.0%. BD carries one of the highest disease burdens. The vast majority of individuals with BD have an additional psychiatric comorbid condition, an array of comorbid medical conditions, an increased rate of unemployment and incarceration, decreased social connections, and shorter life expectancy, whether due to suicide, accidents, or sequela from psychiatric and medical conditions. The underlying neurobiological underpinnings are still relatively unknown, although a significant genetic component exists. Historical treatments have centered on the administration of psychotropic medications, which have helped manage symptoms, but may adversely contribute to medical comorbidities. Just as lifestyle medicine has been successful in improving other chronic health conditions, we will review the pertinent literature and encourage that lifestyle interventions should begin at the onset of the treatment of BD in conjunction with psychotropic medications.

Brain Health

Argueta, D., & Merlo, G. (2023). In Lifestyle Psychiatry (1–, pp. 275-289). CRC Press. 10.1201/b22810-26
Lifestyle psychiatry includes the 6 pillars of lifestyle medicine, all of which partly contribute to brain health across the lifespan. Brain development and well-being across a lifetime require more than treatment or diagnosis; rather, they involve lifestyle factors that offer continual maintenance and improvement of the mind and body. Chronic inflammation in the brain, spine, and/or other nervous tissue (neuroinflammation) has been linked to a variety of brain-related issues, and close investigation of this process can allow us to understand the ways through which mental health, connectivity, and the gut microbiota interact with the brain. Neuroinflammatory factors significantly impact brain health by influencing a diverse range of neural mechanisms in various psychiatric/neurological disorders. Likewise, social connectivity, resilience, meaning in life, happiness, compassion, and spirituality all have implications for neuroinflammation and impact brain health. The brain gut microbiota axis also fundamentally influences brain health and neuroinflammation. We bring together the concepts of neurological disorder, connectivity, and the brain gut microbiota axis to illustrate the mechanisms and importance of brain health within lifestyle psychiatry.

Introduction to Lifestyle Psychiatry

Merlo, G., & Fagundes, C. P. (2023). In Lifestyle Psychiatry (1–, pp. 3-26). CRC Press. 10.1201/b22810-2
Mental health and lifestyle are dynamically interconnected. Current global trends in the prevalence of mental illnesses and chronic disease indicate the need for a transdiagnostic approach to public health that addresses symptomatology, social determinants of health, and individual lifestyle factors to improve health outcomes on individual- and population-level scales. Lifestyle psychiatry is a relatively new but rapidly expanding evidence-based field of medicine that targets health behavior change and patient well-being through the lens of the biopsychosocial model of health. Lifestyle psychiatry may serve as a timely vessel through which lifestyle medicine clinicians can utilize a patient-centered approach to healthcare that enhances mental health, physical health, and overall well-being. Clinical applications of lifestyle psychiatry integrate the foundations of lifestyle medicine, neuroscience related to personality and individual factors, cognitive-behavioral approaches, positive psychology, psychopathology, neurobiology, and health neuroscience.

Lifestyle Psychiatry: Through the Lens of Behavioral Medicine

Merlo, G., & Fagundes, C. P. (2023). (1–). CRC Press. 10.1201/b22810
Lifestyle medicine is a practice which adopts evidence-based lifestyle interventions as a primary modality to prevent, treat, and reverse chronic diseases. The six main pillars of this specialty include physical activity, nutrition, stress resilience, cessation or risk reduction of substance use, quality sleep, and connectivity. Lifestyle Psychiatry: Through the Lens of Behavioral Medicine is grounded in the same pillars, drawing upon theories, methods, and empirical findings from health psychology and behavioral medicine. Lifestyle psychiatry is a rapidly emerging area within healthcare informed by rigorous research within the social and biological sciences, public health, and medicine. A volume in the Lifestyle Medicine series, this book uses a comprehensive biopsychosocial approach to prevent and treat psychiatric disorders and promote mental and physical well-being through evidence-based lifestyle interventions. Features: Draws upon theories, methods, and empirical findings from health psychology and behavioral medicine. Provides evidence-based research on the bi-directionality of mental and physical health. Addresses fundamental neuroscience concepts and applies them to practical aspects of lifestyle practices, mental health, and brain health. Appropriate for clinicians, primary care physicians, and those practicing in specialized areas, the information in this book provides users with practical tools to help explain, prevent, and treat psychiatric disorders and associated maladaptive health behaviors in patients.

LM Initiative Success at the Institutional Level Through the RE-AIM Approach: 12 Tips and Implementation Science Strategies

Ortega, H., Tache, C., Bachtel, G., & Merlo, G. (2023). American Journal of Lifestyle Medicine. 10.1177/15598276231187343
Transforming research into practice via implementation science may improve institution-wide implementation success rates for lifestyle medicine (LM). Implementation science (IS) is the study of methods that facilitate the uptake of evidence-based practice and research into regular use by practitioners and policymakers. Multiple IS frameworks, such as the Reach, Effectiveness, Adoption, Implementation, Maintenance/Practical Robust Implementation Strategy Model (RE-AIM/PRISM) model, Exploration, Preparation, Implementation, Sustainment (EPIS) model, and Consolidated Framework for Implementation Research (CFIR) model, have been developed. IS frameworks provide a strong yet adaptable foundation for launching initiatives, minimizing barriers by challenging implementers to identify and address problems that impede implementation, and promoting long-term sustainability and positive outcomes. The trouble-shooting tips provided in this article are strategically aligned with the RE-AIM/PRISM model of IS to maximize the likelihood of implementation success within the LM space. These tips provide guidance on how to effectively implement interventions, sustain their delivery, and avoid or overcome barriers to implementation. This article presents 12 tips intended as a list of options to facilitate the implementation phases of an initiative, as opposed to offering an all-or-nothing approach to implementation strategy. Current IS priorities emphasize system change and sustainability, which are essential components of successful implementation of LM initiatives.

Nutrition in Lifestyle Psychiatry

Merlo, G., & Bachtel, G. (2023). In Lifestyle Psychiatry (1–, pp. 230-252). CRC Press. 10.1201/b22810-22
An expanding body of research indicates that poor nutrition can change the function of the brain and alter individual behavior and mental health status. The brain is the most energy-consuming organ in the human body. Therefore, maintaining and optimizing brain health, mental health, and psychological functioning depend on a constant supply of nutrients. Data demonstrate that inadequate quality or quantity of nutrition is associated with an increased risk of mental health problems. Lifestyle psychiatry is an approach that aims to address underlying causes or contributing factors to poor mental health and/or mental health conditions, including nutrition. This chapter will discuss nutrition as an integral component of lifestyle psychiatry, as well as a key determinant and factor in mental health outcomes and outcomes for those with mental health disorders. A lifestyle psychiatry approach can help to improve patient outcomes, prevent the onset of mental health and brain health conditions, and enhance the management and treatment of mental health problems by promoting healthy dietary patterns, addressing nutritional deficiencies, and incorporation nutrition-related interventions into clinical practice.

Posttraumatic Stress Disorder

Young, A., & Merlo, G. (2023). In Lifestyle Psychiatry (1–, pp. 342-353). CRC Press. 10.1201/b22810-33
Posttraumatic stress disorder (PTSD) can have profound physical, psychological, and social consequences. Recently, there has been an increase in research on how lifestyle factors, including exercise, nutrition, stress management (e.g., mindfulness), substance use, sleep, and social connectedness may impact psychological and physical health, as well as social outcomes, in those with PTSD. Although research in some of these areas is still limited, results indicate promise for lifestyle interventions in at least some aspects of PTSD treatment. This chapter will explore the evidence for the relevance of these factors with regard to PTSD and discuss any evidence-based lifestyle interventions indicated for PTSD prevention and management.

Primary Care at the Intersection of Lifestyle Interventions and Unhealthy Substance Use

Nakaishi, L., Sugden, S. G., & Merlo, G. (2023). American Journal of Lifestyle Medicine, 17(4), 494-501. 10.1177/15598276221111047
Primary care physicians are well-positioned to integrate lifestyle interventions into the management of patients with unhealthy substance use, who may also have mental and physical chronic health comorbidities. However, the COVID-19 pandemic exacerbated the U.S.’s poor state of health, revealing that its current approach to chronic disease management is neither effective nor sustainable. Today’s full spectrum comprehensive care model requires an expanded toolkit. Lifestyle interventions broaden current treatment approaches and may enhance Addiction Medicine care. Primary care providers have the potential to have the greatest impact on unhealthy substance use care because they are experts in chronic disease management and their frontline accessibility minimizes healthcare barriers. Individuals with unhealthy substance use are at an increased risk of chronic physical conditions. Incorporating lifestyle interventions with unhealthy substance use care at every level of medicine, from medical school through practice, normalizes both as part of the standard care of medicine and will drive evidence-based best practices to support patients through prevention, treatment, and reversal of chronic diseases.

Trauma Considerations

Merlo, G., & Sugden, S. G. (2023). In Lifestyle Psychiatry (1–, pp. 63-70). CRC Press. 10.1201/b22810-6
Trauma is a complex phenomenon that has varying degrees of intensity and impairment for individuals who experience it. As a result, many develop chronic behavioral and physical health sequela that increase their interactions within the healthcare system. The chronicity of these symptoms is further complicated by their overarching adoption of shame, as an unintended chronic coping skill. Shame becomes a master or blanket emotion that suppresses other healthier emotions and healthy interactions with others and the individual’s community. As the majority of individuals have had traumatic exposures, it is hard for healthcare providers to know on the onset which of their patients experience ongoing sequela or not. Subsequently, unintended interactions with the healthcare system have worsened the trauma-related symptoms for many. Over the years, healthcare providers have been encouraged to adopt universal precautions for all blood-borne encounters. Similarly, healthcare providers are encouraged to implement trauma-informed care, universally, to all patients as a means to create healthier environments for healing.