Weight Management
Managing the Side Effects of GLP-1 Therapy
Nausea and constipation are common early in GLP-1 therapy. Here’s what actually helps, and when a symptom is worth a call to your care team.
September 8, 2026
Oakland's Trusted Digestive Health Practice
Comprehensive Gastroenterology, and Specialized Liver & Weight Care.
MacArthur Gastroenterology brings 40+ years of clinical expertise together with physician-supervised programs for fatty liver screening and medical weight management.
Full-scope Gastroenterology Care
From routine colonoscopy and endoscopy to complex GI conditions, our board-certified physicians provide diagnostic and therapeutic care across the full range of digestive health.
Upper GI Endoscopy
EGD is an outpatient procedure using a flexible video endoscope to examine the esophagus, stomach, and duodenum. Performed by Dr. Peterson, it gives a clear, direct view of the upper digestive tract.
Flexible Sigmoidoscopy
Flexible sigmoidoscopy uses a thin, flexible scope with a light and camera to examine the rectum and lower (sigmoid and descending) colon. Learn more from the National Institute of Health (NIH).
Colonoscopy
Colonoscopy uses a flexible fiber optic scope to examine the full colon, from the cecum to the descending colon. Dr. Peterson’s scoping expertise makes this exam both thorough and life-saving.
Fatty Liver Screening
A quick, non-invasive Velacur® scan detects fatty liver disease and liver stiffness in minutes, no needles, no prep required.
Weight Management
Physician-supervised programs, including GLP-1 therapy when appropriate, designed around your metabolic health and monitored by our clinical team.
Meet Your Physician
Care led by Dr. Ralph Peterson
Dr. Peterson has served the Oakland community for over four decades, combining deep clinical experience with a personal, unhurried approach to every patient relationship.
From Our Health Library
Practical guidance on gastroenterology, fatty liver disease, and physician-supervised weight loss, written by our clinical team.
Liver Health
Can Fatty Liver Be Reversed?
Fatty liver disease is often reversible when caught early. Here’s what the research actually shows about how much change is realistic.
September 3, 2026
Weight Management
What “Compounded” Medication Means for Your Program
“Compounded” gets used a lot without explanation. Here’s what it actually means, and what it doesn’t, for your weight management plan.
September 1, 2026
Liver Health
The Sugar and High-Fructose Corn Syrup Liver Connection
Fructose isn’t processed the same way as other sugars. Research increasingly points to it as a direct driver of fat buildup in the liver.
August 27, 2026
Weight Management
Are You a Candidate for Medical Weight Management? (BMI 27+ Explained)
Most clinical guidelines use a BMI of 30, or 27 with a related health condition, as a starting point. Here’s what that actually means and doesn’t mean.
August 25, 2026
Liver Health
MASLD vs. MASH vs. Fibrosis: What the Terms Mean
MASLD, MASH, and fibrosis get used interchangeably, but they’re not the same thing. Here’s what each one actually means.
August 20, 2026
