Start with high-confidence digestive health books, then narrow by subgenre or adjacent topics.
The Mind-gut Connection
Emeran Mayer
Gut Check
Steven R. Gundry MD, Steven R. Gundry
Mind Your Gut
Kate Scarlata, Megan Riehl PsyD AGAF
Super Gut
William Davis M.D.
Healing SIBO
Shivan Sarna
The Bloated Belly Whisperer
Tamara Duker Freuman
Gut Health for Dummies
Kristina Campbell
Gut
Giulia Enders, Jill Enders
Mayo Clinic on Digestive 4th Ed
Sahil Khanna M.B.B.S., Sahil Khanna
Weight Loss Cure
Dr. Mercola