Top Surgeon: This “Healthy” Protein Habit Is Raising Your Cancer Risk—Here's The Quick Fix

April 8, 2026

AI Summary

5 min read

The Hidden Cost of Protein Maxing

Dr. Karan Rajan, a general surgeon who spends his days inside the human body and his nights reading the research, has a warning for anyone chasing sky-high protein targets: the overspill ends up in your colon, where your gut bacteria—starved of fiber and suddenly handed protein—switch modes like "gremlins exposed to water" and start fermenting it. The breakdown products are inflammatory compounds that can damage the gut barrier and shift the gut environment toward a pro-inflammatory state.

The problem isn't protein itself. It's the combination of high protein and low fiber that creates trouble. Rajan estimates that an 80-kilogram athlete maxes out muscle protein synthesis around 170 grams of protein per day—there's no meaningful benefit to going higher. And the primary stimulus for muscle retention isn't protein anyway: "Eating protein and not training is worse for muscle than training and not eating enough protein."

The Fiber Extinction Event

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What you'll learn

1 (01:44) **The Problem with Protein Maxing** - Dr. Rajan explains what happens in the gut when you eat excessive protein.
2 (05:13) **Plant Protein vs. Animal Protein for Weight Loss and Longevity** - The guest addresses the conflict between protein-maxing for weight loss and plant-based recommendations for longevity.
3 (07:13) **What Happens When You Don’t Eat Enough Fiber** - The gut microbiome’s response to fiber starvation is described in vivid detail.
4 (11:10) **The Three Types of Fiber You Need** - A practical framework for feeding your entire microbiome, not just one part.
5 (13:12) **Are “Antinutrients” and Lectins Really a Problem?** - The guest debunks a common fear about plant foods.
6 (14:19) **Why GI Cancers Are Skyrocketing in Young People** - Dr. Rajan breaks down the controllable and uncontrollable risk factors.
7 (16:11) **GLP-1s, Inflammation, and Cancer Risk** - The guest weighs in on the potential long-term effects of these popular drugs.

+ Full timestamped outline available in the app

Guests on this episode

Dr. Karan Rajan

Show Notes

GI cancers are skyrocketing in young people. Colon cancer killed Chadwick Boseman at 43. And, we can all drastically lower our cancer risks almost immediately. In this episode, a top surgeon shares exactly how.

Today’s guest is Dr. Karan Rajan, an NHS surgeon, who has worked with the UN, World Health Organization, and British Red Cross. He shares the three things you can do every single day to lower your risk of GI cancer, what's actually driving chronic inflammation, and the one highest-return, lowest-effort habit for your health—plus he's running through his honest thoughts on cold plunges, seed oils, GLP-1s, saunas, and more sharing exactly what the science says.

🎧 What you’ll learn:

• 3 things to start and stop doing to immediately lower your cancer risk

• Whether or not you're eating too much protein

• What your poop is really telling you (+ how to do an at home poop check!)

• What health trends are worth your time and money

• The difference between fast, medium, and slow fibers

• The resilience of your gut microbiome (+ how to rebuild it after taking antibiotics)

• The supplements and foods Dr. Karan eats daily

Resources mentioned in today’s episode:

• Bristol Stool Chart: https://my.clevelandclinic.org/health/articles/bristol-stool-chart

• FODMAP Information: https://www.monashfodmap.com/about-fodmap-and-ibs/

Check out the previous episode of The Liz Moody Podcast with Dr. Karan:

Ranking Gut Health Advice From Social Media (with Dr. Karan Rajan)

For more from Dr. Karan Rajan:

• Website: https://www.drkaranrajan.com/

• Book: https://www.drkaranrajan.com/book

• Instagram: https://www.instagram.com/drkaranrajan/

Ready to uplevel every part of your life? Order Liz’s book 100 Ways to Change Your Life: The Science of Leveling Up Health, Happiness, Relationships & Success now!

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