About
Tom Flass MD brings an unusually deep nutrition background to his clinical work. He earned a BS in Nutritional Science from Cornell University, then a Master of Science in the same field from Colorado State University. He spent ten years working in nutrition-related fields before entering medical school at the University of Colorado School of Medicine. His residency in Pediatrics and his fellowship in Pediatric Gastroenterology, Hepatology and Nutrition both took place at Children's Hospital Colorado, one of the country's top pediatric training programs.
Dr. Flass holds board certification in Pediatrics and in Pediatric Gastroenterology, Hepatology and Nutrition. He carries 30 years of nutrition experience and 15 years of pediatric gastroenterology practice, the last 12 in Montana. He treats children and adults for a wide range of GI conditions, including Crohn's disease, ulcerative colitis, celiac disease, IBS, SIBO, eosinophilic esophagitis, and food intolerances. He has completed coursework through the Institute for Functional Medicine and is currently awaiting certification. He authored the books Feeding Our Children and Eating For Two, and he co-hosts The Aware Families Podcast. Dr. Flass lives in Kalispell with his wife, two daughters, two dogs, and a flock of chickens. Outside the office, he fishes, tends an orchard, and gardens.
Education & Training
Undergraduate
Cornell University, BS in Nutritional Science; Colorado State University, MS in Nutritional Science
Medical School
University of Colorado School of Medicine
Residency
Residency in Pediatrics, Children's Hospital Colorado
Fellowship
Fellowship in Pediatric Gastroenterology, Children's Hospital Colorado
Additional Training
Institute for Functional Medicine – Program completed, awaiting certification
Certifications
Conditions Treated
Who is Dr. Flass right for?
Dr. Flass is a strong fit for patients seeking root-cause answers to chronic or complex GI problems. Children and adults dealing with IBS, Crohn's, celiac disease, SIBO, or food sensitivities benefit from his integrated approach. His nutrition background makes him especially effective with patients whose symptoms connect to diet, gut health, or dysbiosis. Parents looking for a pediatrician who takes a functional medicine lens to children's health will find his dual expertise valuable. He does not treat GI cancers, including gastric, esophageal, or colon cancer.
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Frequently Asked Questions
Dr. Flass treats a broad range of GI conditions in both children and adults. These include IBS, Crohn's disease, ulcerative colitis, celiac disease, eosinophilic esophagitis, GERD, SIBO, dysbiosis, food intolerances, chronic bloating, constipation, diarrhea, and recurrent nausea and vomiting. He does not treat GI cancers such as gastric, esophageal, or colon cancer.
Yes. Dr. Flass holds board certification in Pediatrics and in Pediatric Gastroenterology, Hepatology and Nutrition. He trained at Children's Hospital Colorado for both his residency and his fellowship in Pediatric Gastroenterology.
Yes. Dr. Flass sees both pediatric and adult patients for GI concerns. His integrative gastroenterology approach applies to patients of all ages dealing with digestive disorders.
Dr. Flass earned both a bachelor's and a master's degree in nutritional science before attending medical school. He then spent ten years working in nutrition-related fields. That foundation gives him roughly 30 years of nutrition experience, which he integrates directly into his gastroenterology and functional medicine practice.
Yes. Dr. Flass completed coursework through the Institute for Functional Medicine and is currently awaiting the completion of his certification. He has incorporated functional medicine principles into his gastroenterology practice for years.
Yes. Dr. Flass offers telemedicine consultations for patients across Montana and in Idaho, Washington, Colorado, and Oregon. In-person visits are available at the Kalispell office.
Dr. Flass authored two books: Feeding Our Children, published in 2021, and Eating For Two. He also co-hosts The Aware Families Podcast, available on Apple Podcasts, Spotify, iHeart Radio, Amazon Music, YouTube, and Audible. He contributes regularly to 406 Woman Magazine and Flathead Living Magazine.
Dr. Flass has practiced pediatric gastroenterology in Montana for 12 years. He founded Functional Medicine Associates of Montana in Kalispell in September 2024 to expand his root-cause, nutrition-forward approach to a wider patient base.
Doctor profile last updated April 2, 2026