Science-Based Nutrition for Gut Microbiome & Metabolic Health

Dr. Rosa Keller is a UCSF- and Oregon State University-trained nutrition scientist and registered dietitian specializing in gut microbiome health, metabolic health, and personalized nutrition.

Through evidence-based nutrition strategies, she helps individuals understand how food influences gut bacteria, inflammation, blood sugar regulation, energy, mood, and overall healthspan.

Her approach combines nutrition science, microbiome research, and practical food strategies to create sustainable improvements in health.

Understanding the Science Behind Your Health

Your gut microbiome plays a powerful role in digestion, immune function, metabolism, inflammation, and overall wellbeing.

Dr. Rosa translates the latest nutrition research into practical strategies focused on:

  • Gut microbiome diversity

  • Gut-brain connection

  • Fiber & prebiotics

  • Polyphenol-rich foods

  • Blood sugar regulation

  • Metabolic health

How Dr. Rosa Keller Helps You Improve Gut Microbiome Health Through Personalized Nutrition

Services

Personalized Nutrition for Gut & Metabolic Health

I offer personalized nutrition counseling and gut microbiome testing to help you understand your unique health needs and develop evidence-based strategies for improving digestion, energy, metabolic health, and overall wellbeing.

Science

The Science Behind Food, Your Microbiome & Your Health

Learn how nutrition influences gut bacteria, inflammation, blood sugar regulation, and long-term health.

  • Gut microbiome diversity

  • Fiber and prebiotics

  • Gut-brain connection

  • Plant compounds and polyphenols

Gut health, metabolic health, and performance nutrition

Dr. Rosa Keller provides Gut health, metabolic health, and performance nutrition across multiple locations. We proudly serve clients in:
Costa Mesa, Anaheim, Yorba Linda, Orange, Tustin, San Francisco and across Orange County
Whether you’re seeking gut health, sport & fitness, or cardiometabolic nutrition, we bring science-backed guidance to your city.

HSA/FSA Eligible Nutrition Counseling

Use your HSA or FSA benefits for eligible nutrition counseling services. Support your gut health, metabolic health, and personalized nutrition goals with evidence-based care.

Check your plan administrator for eligibility.

Science-Backed Nutrition Insights

Smartphone on wooden desk display screen with text 'Get Your Guide' in bold white letters.

Gut Health Guide

Discover the essentials of gut health and learn how to support your microbiome for energy, mood, and overall wellness.

‍ ‍Read Article

Metabolic Health and Nutrition: Why Consistency Matters.

Discover how consistent nutrition habits support metabolic health, stabilize blood sugar, improve energy, and promote long-term wellness.

Read Article

Fermented Foods for a Gut Health

Learn how fermented foods support gut microbiome diversity, digestion, and overall health by providing beneficial bacteria and important nutrients.

Read Article

Frequently Asked Questions

What clients are saying:

Matt M.

“Rosa is the absolute best! She got very specific to help me get on track for my nutritional and fitness goals. She provided gave me guidance on the right types of food I should be eating. In my case, I was most concerned with protein intake. We worked to find high protein but low calorie options. From there, Rosa worked with me on EXACTLY how many grams I should be consuming per day. We worked to plan my meals around this number. She also recommended tasty options that were in line with my nutritional goals. In addition to that, she recommended WHEN I consume my meals to help me most effectively reach my goals. She even recommended a supplement I take that has worked extremely well for me!”

Lisa S.

“Dr. Keller’s extensive knowledge of nutrition science is truly impressive. She empowers you to take control of your health. She is warm and friendly and creates a comfortable and open space for discussion. Instead of pushing a one-size-fits-all plan, Rosa takes the time to understand individual needs and preferences. She focuses on building sustainable healthy habits rather than quick fixes or restrictive diets. I highly recommend Rosa to anyone seeking a knowledgeable, supportive, and compassionate partner.”

Mari F.

“Working with Dr. Keller over the past several months has been transformative in managing my nutrition and weight. Her patience, attentiveness, and unwavering dedication to my progress, both for short- and long-term goals, are truly unmatched. I feel so grateful to have connected with Fay and to be working with Dr. Keller. If you’re looking to change your perspective on food, health, and wellness for the better, I highly recommend her!”