Our Team
Meet Our Team
Dr. Matthew Willis, DC, DABCI - Founder
Board-Certified Diplomate Internist
Dr. Willis is a nationally board-certified diplomate internist (DABCI), and has completed over 10 years of post-doctorate education and holds advanced degrees and certifications in functional medicine, functional nutrition, internal medicine, clinical laboratory diagnosis, nutrigenomics, specialty laboratory testing, & natural treatment of internal disorders. Dr. Willis believes we all deserve a life of great health—and we can create it for ourselves. That’s why he is dedicated to treating the root causes of chronic disease and other modern health issues by using the dynamic model of Functional Medicine, which has been transforming the way healthcare is practiced in today's world as patients demand healthier and more effective alternatives to traditional drug therapy.
He is a practicing doctor, a recognized leader, speaker, author, educator, and advocate in his field. In 2020 and 2021, Dr. Willis was selected by the prestigious Marquis Who's Who in America, and also awarded one of America's Top Doctors, and featured in The Wall Street Journal as a distinguished leader in the field of Functional Medicine. In 2024, he was selected and featured in Millennium Magazine showcasing Advanced Functional Medicine as the face of the movement for drug-less, effective healthcare. Most recently, he was presented with the nationally recognized Albert Nelson Marquis Lifetime Achievement Award for professional integrity, innumerable contributions to society, and outstanding achievements in his respective field.
Dr. Willis is the founder and director of Advanced Functional Medicine of San Diego (awarded best medical clinic in San Diego 7 years consecutive), Advanced Functional Medicine of Orange County and Los Angeles; a speaker for the nonprofit group Doctors for Health and Wellness; has been a regular medical contributor on many functional medicine and integrative health websites around the country. He has been featured on the Discovery Health Channel, Discover Magazine, KUSI news, Fox5 San Diego, San Diego Magazine, The San Diego Tribune, Ranch and Coast, and every iHeart radio station. He is also the author of the best-selling online book The Truth About Type 2 Diabetes. In 2019, Dr. Willis founded Advanced Functional Formulations, a nutraceutical brand of professional-grade supplements created in an FDA-approved facility to help patients overcome a variety of chronic illnesses.
He is a member of the nationally recognized Institute for Functional Medicine, the Council on Diagnosis of Internal Disorders, an active member of the Alzheimer's Family Organization, the Cancer Control Society, as well as a professional member of the American Diabetes Association.
Dr. Sonia Mohan, MD
Co-founder, Director
Dr. Sonia Mohan has years of research experience in pathology at the renowned Cedars Sinai Medical Institute in Los Angeles, CA.
This was followed by post-graduate residency training in the field of Pathology and Laboratory Medicine at Loma Linda University Medical Center. She is now an apprentice of Dr. Willis.
Most recently, seeking a transition from the confines of traditional medicine and learning about the many advantages of a whole-body approach, Dr. Mohan has partnered with the mission of Dr. Willis and now dedicates her career to healing using the latest research in functional medicine.
It is Dr. Mohan’s full intention to target the root causes of illness and embrace the patient’s true path to long-term well-being. Serving as co-owner and medical director of Advanced Functional Medicine has enabled Dr. Mohan to fulfill her patient’s needs in a more comprehensive and fulfilling manner than typical conventional medicine allows.
Lauren Ciavarella
Director of Operations
Lauren has been part of our functional medicine family for over six years, serving as our Director of Operations and resident finance guru. As a proud Penn State graduate, she brings a rare blend of professional intuition and heart to her work, ensuring our clinic runs smoothly while keeping patients at the center of everything we do. She is a problem solver and loves helping patients find flexible, personalized ways to participate in our programs, making functional medicine accessible and achievable for nearly everyone. Her passion for wellness and her dedication to excellence make her an invaluable part of our team. She believes that a simple smile has the power to transform someone’s day.
Dr. Jessica Garcia, PsyD.
Doctor of Clinical Psychology | Holistic Health Practitioner
Dr. Jessica holds a Master's and Doctorate in Clinical Psychology, along with certification as a Transformational Mindset and Holistic Health Coach. With a strong background in early childhood development, she has extensive experience working in hospital, university, and trauma center settings, where she has supported active duty and retired military personnel, as well as children and individuals with diverse neurological and mental health profiles (e.g., autism, ADHD, dyslexia, depression, anxiety, and PTSD). Additionally, Dr. Jessica has worked with individuals experiencing chronic pain in an Integrative Health Intensive Outpatient Program, helping patients navigate both the physical and emotional challenges associated with chronic pain.
Having been exposed to natural remedies in her childhood, Dr. Jessica personally experienced the benefits of holistic health. After facing her own health challenges that weren’t fully addressed by conventional medicine, she sought out functional medicine, which played a transformative role in her own healing journey. While she had incorporated holistic practices in her previous roles, she recognized their limitations within traditional settings, which ultimately led her to pivot toward functional medicine. Today, she is passionate about helping others in the same way she was helped.
In addition to her clinical training, Dr. Jessica has expanded her expertise in fitness, nutrition, holistic psychology, and Functional Medicine. She is committed to empowering her patients to reclaim control of their health by guiding them toward a holistic approach. This includes nourishing food, regular physical activity, and relaxation practices designed to promote balance and overall well-being. Dr. Jessica believes these foundational principles are key to managing the everyday stressors of life while supporting optimal health and longevity.
*Fluent in both English and Spanish, Dr. Jessica is dedicated to making holistic health and mental well-being accessible to a range of clients.
Dr. Grace Victor, ND
Naturopathic Medical Doctor
Dr. Grace is a CA Licensed Naturopathic Doctor. She earned her Doctorate in Naturopathic Medicine from Bastyr University in San Diego, CA. Her journey to Naturopathic Medicine began after completing her undergraduate degree with a desire to find a model of medicine that focuses on chronic disease management and prevention, and a patient-centered healthcare model that allows patients to heal from the inside—not just mask symptoms with pharmaceuticals.
Dr. Victor was drawn to the success of the Functional Medicine healthcare model at Advanced Functional Medicine. Her passion is to support patients on their healthcare journey through utilizing nutrition, botanical medicine, homeopathy, lifestyle, and nutrient supplementation. Outside of the office, Dr. Victor enjoys spending time with her family, and enjoying the sunny SoCal weather!
Sara Leckman, BSN, RN, HHC
REGISTERED NURSE, FUNCTIONAL HEALTH COACH
Sara is a Registered Nurse and Board-Certified Health and Wellness Coach originally from Washington State where she completed her Bachelor’s degree in the Science of Nursing at Seattle Pacific University. Before joining the team at Advance Functional Medicine, Sara worked as a Nurse Clinician at a Community Health Clinic in Seattle, where she practiced chronic disease management and led diabetes education programs. Early on in her career, she recognized that the conventional-medicine model fails to identify and treat the root cause of disease, and often leaves patients desperate for more help. Sara decided that she could no longer be a part of the ineffective and costly medical system that simply “manages chronic disease”. In search of something greater, Sara discovered the power of Functional Medicine. Since then, Sara has completed additional training in Nutrition, Holistic Nursing, and Functional Medicine.
Sara believes the human body is innately intelligent and fully capable of healing given the right environment. As an RN Health Coach, Sara sees her patients as active participants in their care, as they are supported in creating lasting-lifestyle change. Sara’s mission is to educate and empower patients to take back control of their health. What Sara loves most about her role here at Advanced Functional Medicine, is seeing patients get off numerous prescription medications while they continue to reverse disease and live more fulfilling lives.
Stacy Antone
FNP-C
Stacy is a Nurse Practitioner practicing functional and integrative medicine with an emphasis on bioidentical hormone replacement therapy. Her approach centers on identifying and correcting underlying imbalances rather than simply treating symptoms, using comprehensive assessments, lifestyle medicine, and customized BHRT protocols to support optimal hormone function and overall well-being. Stacy partners closely with individuals seeking renewed energy, better sleep, improved mood, and restored vitality. She is passionate about education and empowerment, helping her patients understand their physiology so they can make confident, informed decisions about their health. Through a blend of scientific rigor and holistic insight, Stacy guides patients toward sustainable wellness and a more vibrant quality of life.
Alfonso
Clinic Director / FNMS
Alfonso has a strong background in functional nutrition, metabolic health, and behavior-based coaching, Alfonso helps patients make sense of what they’re experiencing and what steps will best support their recovery. As a Functional Nutrition and Metabolism Specialist (FNMS) and certified Health & Wellness Coach, he bridges the gap between patients’ concerns and the clinical direction they need, always with clarity, empathy, and practicality. His calm, educational communication style, and bilingual fluency, makes him an approachable guide for patients navigating the first steps of their healing journey.
Before joining the clinic, Alfonso built a successful, data-driven coaching practice working with busy, high-performing women who struggled with chronic gut issues, autoimmune-related symptoms, thyroid dysfunction, weight-loss resistance, fatigue, bloating, recurrent inflammation, and hormone imbalance. His ability to decode lab data and connect it to real-world nutrition, training, and lifestyle practices helped hundreds of women improve digestion, balance hormones, restore energy, and make sustainable body-composition changes.
Outside the clinic, you’ll often find Alfonso chasing his three daughters at the beach, sneaking in guitar sessions between naps and homework, lifting heavy weights, cooking good food, or enjoying a well-earned moment of sunshine with his family. His personal commitment to balance, movement, and vitality mirrors the very principles he teaches, living proof that a healthy life should feel both grounded and enjoyable.
Michael Stricker
Clinic Director
Michael comes with almost a decade of experience in geriatric healthcare, working closely with patients in hospice and memory care/assisted living communities. His experiences in these settings inspired a passion for preventive and holistic approaches to wellness. Now working in functional medicine, Michael focuses on helping patients understand how lifestyle, nutrition, and personalized care can improve their health and quality of life long before the later stages of aging. His goal is to empower individuals to take an active role in their well-being and create lasting, meaningful changes for a healthier future.
Lisa Murray, MS
Practitioner / Admissions Director
Lisa Murray is a Clinical Nutritionist with 15 years of experience in both clinical settings and health-based start-ups. She completed her Bachelor's degree in Education at San Diego State University and her Masters in Nutrition Science (MS) at American University in DC. Throughout her career, she has provided expert care, support, and leadership to hundreds of clients and teams. Whether developing app-based nutrition programs, consulting with patients, or analyzing comprehensive lab work, Lisa integrates an integrative and evidence-based approach to wellness.
Her specialties include integrative weight management, longevity and anti-aging protocols, diabetes care, and women's health. She is dedicated to empowering individuals and organizations with personalized, science-backed solutions that drive meaningful health outcomes.