About Us
Learn about our team that is here to help you achieve long-term success.Dr. Robert Kistler – Owner / Physician
Dr Kistler has enjoyed an active family medical practice for over 30 years in his hometown of Lufkin, where he developed his skills and dedication to treating obesity. Since opening MediSlim in 2017, he has focused on caring for those with weight issues. Dr Kistler is passionate about the practice of obesity medicine and is committed to working with his patients to “treat the roots, and not the fruits” of the disease. “Nothing has been more satisfying than partnering with an overweight individual, seeing them reach their goals and reaping the benefits of a healthier, more active, confident life.”
Dr Kistler attended Baylor University, UTMB Medical School in Galveston, and the Waco Family Medicine Residency Program in Waco, Texas. He is a member of the American Association of Family Practice, the Obesity Medical Association, and The Obesity Society.
When not working at MediSlim, Dr. Kistler can be found enjoying pickleball, golf, or chasing after his grandkids.
Desiree Holley – PA-C
Desiree Holley is a Physician Assistant with 20 years of experience after graduating in the top 5 percent of her class from the University of North Dakota. Since joining Dr Kistler at the MediSlim Rayburn Clinic in 2020, she has developed a passion for medical wellness and seeks to improve individual health outcomes through weight management.
Desiree is excited to continue her journey serving and helping others reach their health goals. She has been an active community member of Sam Rayburn for over 30 years and enjoys the outdoors, staying active, and playing sports like pickleball and golf.
Angela Larson – Registered Dietician Nutritionist
Angela Larson is a Registered Dietitian Nutritionist passionate about integrating practical and approachable lifestyle changes with nutrition science. When she’s not working with clients to help them achieve health and weight management goals, she’s taking care of her four daughters. Angela especially enjoys studying her Bible, cooking, gardening, and spending time with family.
Cassandra Richardson – Office Manager
Cassandra Richardson is an office management professional with over 25 years of industry experience. She joined the team as a medical billing specialist and is now the office manager for MediSlim. She is dedicated to assisting each individual to maximize their experience with us.
Please feel free to reach out to her concerning any issues. She possesses excellent leadership and organizational skills and ensures the effectiveness of the company’s staff and processes.
Cassandra attended Lamar University in Beaumont, Texas. She is a native of Beaumont, TX, and enjoys creative decorating and design. She also enjoys three wonderful, very active, precious young grandchildren.
Tabitha Duff – M. A.
I started my career as a Medical Assistant with a family practice in Livingston, then transitioned to their weight loss clinic as an office manager and Medical Assistant. Weight loss coaching soon became my passion, and for the last 30 years, I have dedicated myself to helping others achieve their weight loss goals.
I am a happily married mother of two. I enjoy spending time with family and friends, cooking, entertaining, and outdoor activities.
Brooke Cassell – M.A.
My name is Brooke Cassell, and I’m from Tenaha, TX. I am a medical assistant, and I worked five years for Lone Star Family Medicine in Lufkin, TX, and one year at Texas Quick Care in Center, TX. Interacting with patients is something that I love the most about my job. I love being around people and making new friends. I have three kids: Callianna, 16; Caitlyn, 12; and Case Cassell, 8. I spend most of my free time watching my kids play in their extracurricular activities, driving them around to the many places they think they need to go, or just hanging out at home.