Ranking Gut Health Advice From Social Media (with Dr. Karan Rajan)
March 30, 2026
AI Summary
5 min readRanking Gut Health Advice From Social Media
Dr. Karan Rajan, an NHS surgeon trained at Imperial College London, joined Liz Moody to sort through the most popular gut health advice circulating online. They ranked claims from S tier (superior) down to F tier (leave behind), and the conversation revealed that much of what goes viral is either incomplete, overhyped, or flatly wrong.
The Fiber Imperative
The strongest consensus of the episode was that fiber deserves a tier above S. Rajan called it "the powerhouse of metabolic health, immune regulation, inflammatory function, hormonal regulation." He pointed to the Hadza tribe in Tanzania, who eat upwards of 100 grams of fiber daily and have bacterial species that don't even exist in Western populations—along with the lowest rates of chronic disease in the world.
The current recommended 25–38 grams per day is based on "outdated epidemiological and nutritional research," Rajan said. He personally reversed high cholesterol and fatty liver disease by increasing his fiber to 50–55 grams daily, and he wants the baseline recommendation moved closer to 40 grams.
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What you'll learn
- 1 (00:05) **Introduction: Ranking Gut Health Advice** - Liz Moody introduces the episode's premise: ranking social media gut health advice from S tier (superior) to F tier (leave behind), joined by NHS surgeon Dr. Karan Rajan.
- 2 (01:23) **S Tier: Probiotic & Prebiotic Food Synergy** - A TikTok claiming that pairing probiotic-rich foods (sauerkraut) with prebiotic foods (kiwi) amplifies gut benefits is played and evaluated.
- 3 (04:02) **B Tier: Bone Broth for Gut Barrier** - A TikTok claims bone broth's amino acids (glycine, glutamine) soothe and strengthen the gut barrier; Dr. Rajan assesses this claim.
- 4 (06:55) **Dr. Rajan's Protocol for Gut Barrier Function** - He outlines four pillars for improving gut barrier function beyond trendy supplements.
- 5 (09:37) **S Tier: Fiber's Full-Body Benefits** - A TikTok from Wellness by Naomi lists fiber's benefits beyond digestion (hormonal breakouts, blood sugar stability); Dr. Rajan fully endorses this.
- 6 (12:18) **The Fiber Fart Curve: Managing Bloating** - Dr. Rajan explains why people get gassy when increasing fiber and how to push through it.
- 7 (15:05) **Raising the Fiber Baseline** - Dr. Rajan argues the standard 25-38g fiber recommendation is outdated.
+ Full timestamped outline available in the app
Guests on this episode
Show Notes
We’re following all of the gut health advice on the internet and our guts feel maybe worse than ever. We’re bloated, we’re constipated, AND all of the videos we’re watching are contradicting each other. Do we have leaky gut? Should we be fibermaxxing? Why does the fiber make us fart so much?
On the Liz Moody Podcast, we're always looking for the real science that can actually change our lives, so today I'm joined by Dr. Karan Rajan, an NHS surgeon, who has worked with the UN, World Health Organization, and British Red Cross.
We're ranking gut health advice from social media, from the best advice to the advice you should definitely ignore.
🎧 What you’ll learn:
• The truth about leaky gut
• Why polyphenols are a secret weapon for gut health
• How to increase fiber without the gas
• A 4-step protocol for strengthening your gut barrier
• Prebiotics vs. probiotics
• The real reason coffee makes you poop
• Whether gluten, dairy, and cold drinks are harming your gut
• How to train your gut
Check out the previous ranking episodes of The Liz Moody Podcast:
• Healthy Eating Advice: Ranking Best & Worst From Social Media (with Nutrition By Kylie)
• Therapy Advice: Ranking Best & Worst From Social Media (with Lori Gottlieb)
• Money Advice: Ranking Best & Worst From Social Media (with HerFirst100K)
For more from Dr. Karan Rajan:
• Website: https://www.drkaranrajan.com/
• Book: https://www.drkaranrajan.com/book
• Instagram: https://www.instagram.com/drkaranrajan/
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