Kari Natwick, RDN, LD, IFNCP, CGN

Kari Natwick, RDN, LD, IFNCP, CGN, is an integrative and functional dietitian, educator, and founder of Kari Natwick Nutrition. Known professionally as the GutBrain RD, she brings more than 20 years of experience in clinical nutrition, education, leadership, and telehealth.

Kari specializes in complex gastrointestinal conditions, including IBS, SIBO, GERD, and IBD, with particular expertise in the gut-brain connection and the relationships between digestive health, brain fog, cognition, anxiety, depression, and other mental health concerns. Her clinical work also includes autoimmune and thyroid disorders, mold and mycotoxin-related illness, and women’s health during perimenopause and midlife.

Her personalized, systems-based approach uses food as medicine and integrates comprehensive health histories with conventional biomarkers and functional testing. Her experience spans gastrointestinal, hormonal, organic acid, mycotoxin, micronutrient, mineral, and blood chemistry assessment. Kari has also completed the yearlong Functional & Integrative Medicine Professional Training Program with Aviva Romm, MD, and has advanced training in the evidence-informed use of herbs and botanicals.

Her perspective is informed by both her clinical work and her personal experience navigating Hashimoto’s, mold-related illness, and perimenopause. Kari has taught dietetic interns, nursing students, multidisciplinary healthcare teams, and other health professionals and is known for translating complex science into practical, individualized care.