Best Tools for Gut Health & Weight Loss | Dr. Chris Thompson

Episode of Huberman Lab · September 21, 2026 · 2 h 28 min

Andrew Huberman and gastroenterologist Chris Thompson discuss gut anatomy, fiber and the microbiome, GLP-1 drugs, early metabolic testing, gut permeability, and endoscopic and gene-therapy obesity treatments.

Summary

Andrew Huberman interviewed Chris Thompson, a Harvard gastroenterologist and chief of interventional gastroenterology at Mass General Brigham, about the digestive tract and metabolic health. Thompson walked through the esophagus, stomach, small bowel and colon, describing conditions such as achalasia, Zenker's diverticula and colon cancer, and recommended colon cancer screening starting at 45. He argued that fiber and low-sugar fermented foods are essential to feed the microbiome, which produces butyrate that maintains the gut barrier, and said the benefits of time-restricted eating outweigh any microbiome risks.

On GLP-1 receptor agonists, Thompson said he was grateful for the drugs but noted high discontinuation rates, nausea, and loss of lean mass, warning that cycling on and off worsens body composition. He described patients successfully microdosing for maintenance and recommended resistance training. He traced the history of incretin research from 1930s duodenal extracts through the discovery of exendin-4 in Gila monster venom, and argued that metabolic dysfunction follows a predictable sequence detectable early through continuous glucose monitoring, fasting insulin, markers of ectopic fat, HOMA-IR and respiratory exchange ratio testing. Huberman criticized medical pushback against patients obtaining their own data; Thompson largely agreed, while noting concerns about incidental findings on whole-body MRI.

Thompson described innovations he helped develop, including a biopsy needle for pancreatic cancer diagnosis, endoscopic sleeve gastroplasty (ESG), which he developed in 2012, fundal ghrelin-cell ablation, duodenal ablation, magnetic anastomosis, and AI-guided procedural coaching and grading. He said increased gut permeability is real and linked to metabolic disease, though he cautioned against blaming "leaky gut" for everything. He closed by describing an endoscopically delivered gene therapy that makes pancreatic beta cells co-secrete GLP-1 with insulin, which he said had entered clinical trials, and reflected on being a lifelong tinkerer.

Chapters

2:56
A tour of the digestive tract
Thompson describes the functions and disorders of the esophagus, stomach, small bowel and colon, including achalasia and colon cancer screening.
Linked moment · 13:40Skip to 13:40 using a listen link in the info box.
13:40
Swallowing problems and bowel health
Thompson explains food coming out the nose, Zenker's diverticula, and rules of thumb for healthy bowel movements.
18:28
Fiber, fermented foods and fasting
The two discuss fiber, resistant starch, fermented foods, butyrate, and whether intermittent fasting harms the gut.
27:10
Ulcers and H. pylori
Thompson explains that H. pylori causes ulcers but that ischemia, acid and stress also contribute.
30:12
GLP-1 drugs, adherence and microdosing
Thompson discusses why patients stop GLP-1 drugs, muscle loss, and microdosing for maintenance.
39:49
History of bariatric surgery and medical regulation
Thompson recounts the evolution from jejunoileal bypass to modern bariatric surgery and discusses off-label and compassionate device use.
47:24
Hunger hormones and the incretin story
Thompson lists ghrelin, CCK, GIP, PYY, GLP-1 and leptin and recounts the history leading to exendin-4.
59:32
Early detection of metabolic dysfunction
Thompson outlines the sequence from glucose spikes to metabolic inflexibility and the tests to detect each stage, and the two debate physician resistance to patient data.
1:25:31
AI, robotics and surgeon quality
Thompson describes AI coaching during procedures, robotics shortening learning curves, and objective grading of surgeons.
1:42:39
Foregut exclusion and duodenal research
Thompson describes the fistula case that led him to study gut hormones, duodenal liners, ileal interposition, and duodenal ablation.
1:52:58
Leaky gut and gut permeability
Thompson presents evidence that increased gut permeability is real and tied to metabolic disease while cautioning against overattribution.
1:58:57
Sweeteners, oils and omega-3s
The two discuss artificial sweeteners, fructose, seed oils, olive oil, and omega-3 supplementation.
2:04:35
Exercise, set point and endoscopic procedures
Thompson explains the defended weight range and how ESG, ghrelin ablation and magnetic anastomosis target specific mechanisms.
2:16:49
GLP-1 gene therapy and Thompson's background
Thompson describes a pancreatic GLP-1 gene therapy entering trials and reflects on being a tinkerer drawn to hands-on medicine.

Key points

What was said, by whom, with the exact words. Timestamps jump to the moment.

Chris Thompson
Thompson says colonoscopy is not an ideal screening method and expects blood and stool tests to replace it as technology improves.
“Colonoscopy is not a great way to do screening, right? You shouldn't have to have a relatively invasive procedure to be screened for something”
Listen from 10:08 · Colorectal cancer screening
Chris Thompson
Thompson argues that gut microbes deprived of fiber will consume the mucus layer and fail to produce butyrate needed for tight junctions.
“And if you're not feeding them fiber, they'll eat your mucus layer, okay? And we already talked about how thin that barrier is”
Listen from 21:27 · Dietary fiber
Chris Thompson
Thompson believes the benefits of time-restricted eating outweigh potential risks to the gut lining from fasting.
“So I do think the benefit of the time-restricted eating definitely outweighs that potential”
Listen from 23:02 · Gut microbiome
Chris Thompson
Thompson argues fermented foods are missing from the Western diet and act as both prebiotic and probiotic.
“I think they're important and they're missing in the Western diet, which is an issue”
Listen from 24:11 · Fermented foods
Chris Thompson
Thompson reports that about 30% of patients stop GLP-1 drugs in the first month and about half by year's end, similar to other chronic medications.
“About 30% come off GLP-1s in the first month and then 50% or so by the end of the year, right?”
Listen from 31:30 · GLP-1 receptor agonists
Chris Thompson
Thompson warns that cycling on and off GLP-1 drugs shifts body composition toward more fat and less muscle each cycle.
“So now basically you're taking your body composition and shifting it worse every cycle. So there has to be a game plan”
Listen from 34:31 · GLP-1 receptor agonists
Chris Thompson
Thompson says many of his patients microdose GLP-1 drugs for maintenance, which he views as a form of personalized medicine.
“I was like, wow, that's actually, that's a great idea. So a lot of my patients actually do microdose these things”
Listen from 35:23 · GLP-1 receptor agonists
Chris Thompson
Thompson cites the Whitehall II study showing elevated fasting insulin predicted diabetes up to 15 years earlier, yet it is rarely checked.
“They could detect this thing 15 years earlier. They could do something about it, right? But no one does because no one looks for fasting insulin”
Listen from 1:07:16 · Insulin resistance and metabolic syndrome
Chris Thompson
Thompson recommends wearing a CGM for a month or two to learn which foods spike glucose rather than wearing one permanently.
“I wouldn't say wear it all the time, get one for a month or two, learn what spikes your glucose, see if something spikes your glucose and adjust it”
Listen from 1:09:51 · Continuous glucose monitoring
Andrew Huberman
Huberman argues that physicians who resisted patients obtaining CGM and lab data have largely come around, and that such pushback tends to fade.
“But now that CGMs have been out for a couple of years, I don't hear much pushback”
Listen from 1:17:06 · Continuous glucose monitoring
Chris Thompson
Thompson argues that more diagnostic information is almost always better, though he acknowledges whole-body MRI can trigger risky follow-up tests.
“But again I think more information is better, almost in all circumstances, with diagnostic stuff”
Listen from 1:22:27 · Continuous glucose monitoring
Chris Thompson
Thompson says in his lab's research, trainees using robotics performed a complex tumor resection almost as well as experts, compared with years of learning by the traditional method.
“That's why it takes two or three years to learn how to do it. They'll sit down with a robot and be almost good as an expert”
Listen from 1:28:11 · Artificial intelligence in surgery
Chris Thompson
Thompson advocates using AI to objectively grade procedures and sharing those grades with credentialing bodies and patients.
“It would be nice for patients to be able to select who they're gonna go to based on objective metrics”
Listen from 1:29:38 · Artificial intelligence in surgery
Chris Thompson
Thompson recounts that closing gastrogastric fistulas resolved diabetes in 60% of patients, while none resolved without closure.
“And where we closed the fistula, 60% of people had resolution to their diabetes. If we didn't close it, no one got resolution to diabetes”
Listen from 1:45:00 · Bariatric surgery
Chris Thompson
Thompson affirms that increased gut permeability is real and tied to metabolic illness but cautions against blaming it for everything.
“And you do see where this increased gut permeability is associated, hardcore, good science evidence with real illness. So absolutely is a problem. It's just, I don't want to blame it for everything”
Listen from 1:57:07 · Intestinal permeability
Chris Thompson
Thompson says high fructose corn syrup should be treated like alcohol, though fructose in whole fruit is fine.
“i think they're better than high fructose corn syrup for sure right i mean that i think we should be treating like alcohol”
Listen from 2:00:21
Chris Thompson
Thompson explains that after crash dieting the body defends its prior weight range through hormonal and metabolic adaptations.
“So your whole body is fighting you, okay? It wants to go back to that weight, whatever it thought it was supposed to be at”
Listen from 2:06:42 · Body weight set point
Chris Thompson
Thompson states that adding fundal ghrelin-cell ablation to ESG raises weight loss from about 18% to over 20%, possibly 25%.
“So the weight loss goes from about 18% with the ESG alone in a top center, goes up to way over 20%, maybe 25% if you start ablating the ghrelin”
Listen from 2:09:08 · Ghrelin
Andrew Huberman
Huberman suggests biology favors combinatorial approaches like retatrutide over pushing hard on a single lever.
“maybe the more combinatorial approach is the better approach. I'm speculating here, but there seems to be a parallel theme”
Listen from 2:13:47 · GLP-1 receptor agonists
Chris Thompson
Thompson argues that procedures and drugs will fail unless patients also fix fundamentals like diet, fiber, and exercise.
“the surgeries the medicines will fail unless you really address those underlying problems”
Listen from 2:16:34 · Body weight set point
Chris Thompson
Thompson describes a gene therapy that makes pancreatic beta cells co-secrete GLP-1 with insulin in a nutrient-responsive way, delivered by endoscopic ultrasound.
“So basically, when a patient would secrete insulin in a nutrient-responsive way, they'd simultaneously be secreting GLP-1”
Listen from 2:17:49 · Gene therapy
Chris Thompson
Thompson says the GLP-1 gene therapy has entered clinical trials, possibly in the Netherlands, and could become a one-time treatment.
“They actually just entered clinical trials in, I think, the Netherlands. So it's very exciting. So we'll see how that goes”
Listen from 2:20:48 · Gene therapy

People

In the conversation

Andrew HubermanAmerican neuroscientist, professor at Stanford School of Medicine and host of the Huberman Lab podcast
Chris ThompsonProfessor of medicine at Harvard Medical School and chief of interventional gastroenterology at Mass General Brigham

Discussed

Barry MarshallAustralian physician who showed H. pylori causes gastric ulcers, partly through self-experimentation
Justin SonnenbergStanford microbiologist whose study linked low-sugar fermented foods to reduced inflammation
Sheila SherlockBritish physician regarded as a founder of hepatology, whose lab studied the incretin effect
John EngBronx researcher who discovered exendin-4 in Gila monster venom
William BruggeInterventional gastroenterologist and endoscopic ultrasound pioneer who mentored Thompson
Edward MasonSurgeon credited with developing gastric bypass surgery
Francesco RubinoSurgeon whose rat studies on foregut exclusion influenced diabetes surgery research

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