Your head is not in charge. Your gut is.

What is The Angry Gut about?

The Angry Gut: The First Brain: Older Than Thought, and Still in Charge is the third book in The Brain series, written by Dr. Gurpreet Singh Padda, MD, MBA, MHP, with Ami Michelle Grimes. Nectar Media Group published it on September 16, 2026 (ISBN 978-0-9832058-2-1), in paperback and Kindle on Amazon.

The anatomy chart says the brain commands and the gut obeys. The chart is upside down.

The book covers what an inflamed, leaking, badly fed gut does to the brain that thinks and to the nervous system that hurts: what causes it, how it is measured, and what the evidence says about correcting it. Its instruction is one line: treat the first brain before you try to fix the second.

Why is the gut the first brain?

Because evolution built it first, and the order still holds.

Before chordates existed, primordial organisms were essentially digestive tracts that consumed and grew. The human gut is the outer surface of the animal folded inward into a tube, and the villi lining it dwarf the skin on the outside. The organ in the skull arrived millions of years later, tethered to the first by the vagus nerve.

The first brain never gave up control.

• It runs its own nervous system, with roughly as many neurons as the spinal cord: 168 million.
• It manufactures the overwhelming share of the body's serotonin.
• The part of the vagus serving it is built almost entirely of thin, slow fibers that carry reports. The traffic runs mostly upward.

The second brain is downstream. It reads what the first one sends. When what it sends is fire, the second brain reports anxiety, cravings and pain.

What are the thirty-three chapters?

Chapter 0 sets the evolutionary premise. The thirty-two that follow work through the wall, the wire, the flora, the bile, the drugs and the food supply.

0. The Primordial First Brain. Stomach of a hyena.
1. The First Brain on Fire. Anxiety is gut fire.
2. The Pharmaceutical Acid Wash. Nobody works in the bag. Two-thirds of your pill is not the drug.
3. The Vagal Highway. Two doctors, one nerve.
4. The Permeable Fortress. The leaky gut test you paid for cannot see the wall.
5. The Fatty Liver Furnace. Alcohol you never drank.
6. The Intrinsic Factor Failure. Normal is not fine: the normal B12 that was not.
7. The Collagen Collapse. Collagen is the wall.
8. The Lipid Fire. What you fried last week.
9. The Nitric Oxide Crisis. Your gut is suffocating.
10. The Sunshine Hormone. It is a hormone.
11. The Disc Microbiome. Bacteria in your spine.
12. The Second Brain Microbiome. Waistline predicts a leaking brain.
13. The Trauma Blueprint. Fear paralyzes the gut. Two doctors, one bowel, and nobody in charge.
14. The Starved Enterocyte. Full of calories, starving one cell deep.
15. The Artificial Food Supply. Your microbes read the label, not the macros.
16. The Immune Matrix. The immune system is not confused.
17. The Sleep Deprived Microbiome. Your gut has jet lag.
18. The False Parasite. The wrong enemy.
19. The Metabolic Fast. Six meals a day is a business model.
20. The Hypochlorhydria Myth. The heartburn pill you cannot quit.
21. The Narcotic Bowel. The pain pill that paralyzes your gut. Side effect or disease?
22. The Glyphosate Harvest. The antibiotic on your salad.
23. The Bile Acid Disconnect. Bile is a hormone.
24. The Cravings of the Dysbiotic Mind. Your sugar craving has a schedule.
25. The Diagnostic Breath and Biomarker. Your gut exhales its secrets.
26. The Biotoxin Blueprint. Fix the basement first.
27. The Eradication and Repopulation Paradox. The weeds were never the problem.
28. The Biliary Flush. Where does bile go?
29. Rebuilding the Mucosal Fortress. Measure the wall. A plateau is not a personality.
30. The Integrated Terrain. There is no discharge date.
31. The Histamine Storm. Not allergic. Fermenting it.
32. The Nicotine Paradox. It was never the molecule. It is where you put it.

How are the chapters organized?

By where the fire starts.

• The wall. The Permeable Fortress, The Collagen Collapse, The Starved Enterocyte, Rebuilding the Mucosal Fortress. Collagen is the wall. Starve the cells that build it and it leaks.
• The wire. The Vagal Highway and The Trauma Blueprint. One nerve, two doctors, and fear that paralyzes the gut.
• The flora. The Second Brain Microbiome, The Sleep Deprived Microbiome, The Cravings of the Dysbiotic Mind, The Eradication and Repopulation Paradox. The weeds were never the problem.
• The bile. The Bile Acid Disconnect and The Biliary Flush. Bile is a hormone.
• The drugs. The Pharmaceutical Acid Wash, The Hypochlorhydria Myth, The Narcotic Bowel, The Nicotine Paradox. The heartburn pill you cannot quit, and the pain pill that paralyzes the bowel.
• The food supply. The Lipid Fire, The Artificial Food Supply, The Metabolic Fast, The Glyphosate Harvest. Your microbes read the label, and six meals a day is a business model.

Chapter 30, The Integrated Terrain, pulls it back together. There is no discharge date.

Does gut serotonin control mood?

No. And the book says so in Chapter 1, against its own interest.

Dr. Padda taught for years that gut-made serotonin runs your mood. It would make the book easier to sell. It is wrong. The gut does make the overwhelming share of the body's serotonin, and serotonin cannot cross the blood-brain barrier. There is no tanker of calm running from the colon to the cortex.

Chapter 0 does the same to the tidy vagal fiber ratio everyone quotes. Nobody has counted those fibers in a human vagus.

Both corrections weaken a case the book is making. Both are printed.

What is inside each Deep Dive?

Every chapter has a Deep Dive, reached from the code printed in that chapter. It is the chapter, continued:

• more of the evidence behind it,
• the strongest case against it,
• and what would change Dr. Padda's mind.

That last item is the rare one. A claim that names the evidence that would overturn it can be tested. A claim that does not is a sales pitch. Where the evidence is mixed, both sides are on the page. Where a trial argues against the chapter, that trial is printed.

The Deep Dives go further than the chapters have room to, and they are the reason the series takes as long as it does.

Request one and it arrives by email straight away. The remaining thirty-two arrive one a week, in the book's own order.

Is there a video for each chapter?

Yes. All thirty-three chapters have their own video with the chapter's slides. Chapter 0, The Primordial First Brain, sets up the whole argument. Start there.

Who should read The Angry Gut?

• People with reflux, bloating or an irritable bowel who were handed an acid pill and a shrug.
• People on acid suppression for years. Several chapters cover these drugs, and they are not safe to stop abruptly without supervision.
• People whose anxiety or sugar cravings seem to live in the stomach.
• Pain patients whose bowel stopped working on their pain medication.
• Physicians who want the gut-brain evidence with the counter-evidence attached.

The book is educational. Significant dietary change needs medical supervision for anyone on medication for diabetes or blood pressure, anyone pregnant or breastfeeding, and anyone with kidney, liver, gallbladder or pancreatic disease or a history of disordered eating.

Can I have my gut terrain evaluated in St. Louis?

Yes. The book tells you what to measure. It cannot tell you what your gut is doing.

Dr. Padda sees patients in person in St. Louis. A terrain evaluation looks where the book looks: what the intestinal wall is built from, what the flora are being fed, what years of acid suppression and antibiotics have done to the chemistry, and the inflammatory load most panels never test for. Then it builds one plan across all of it.

Evaluations run through Regen.MD, and the Padda Institute is where to have it looked at properly. Text (314) 886-5902. Outside the St. Louis area, take the book to your own physician.

Who wrote The Angry Gut?

Dr. Padda is an interventional pain physician in St. Louis who treats the terrain, not the symptom. He wrote this book with Ami Michelle Grimes. He holds five American board certifications, in obesity medicine, addiction medicine, interventional pain, pain medicine and anesthesiology, and is a Diplomate of the Society of Metabolic Health Practitioners and an advisor to the Nutrition Network.

He performs injections and ablations and is direct about what they are for: symptom control now, which buys the time and mobility to repair the terrain. A bridge, not the whole plan. What he avoids is the destructive operation that burns the bridge behind it. His full record is on the Dr. Gurpreet Singh Padda page.

The Angry Gut is book three of five; the full set is on The Brain book series page. Not sure where to go next? Tap the directory assistant, the light in the corner of this page.

The lining of your gut has rebuilt itself every few days since the day you were born. It will keep doing it, for as long as you stop setting it on fire.

Frequently asked questions

Is a leaky gut test worth paying for?

Chapter 4 argues the commercial leaky gut test you paid for cannot see the gut wall. Chapter 25 covers the breath tests and biomarkers the book does discuss.

Can I just stop my heartburn medication?

No. Several chapters cover acid suppression, and it is not safe to stop abruptly without supervision. Chapter 20 explains why the pill is so hard to quit.

How can I have fatty liver if I do not drink?

Chapter 5, The Fatty Liver Furnace, covers the liver that looks like it processed alcohol you never drank.

Can my back pain involve bacteria?

Chapter 11, The Disc Microbiome, covers the evidence for bacteria in the spinal disc.

Is eating six small meals a day healthy?

Chapter 19 calls six meals a day a business model and makes the case for the metabolic fast.

Why do my sugar cravings come at the same time every day?

Chapter 24 ties the schedule of a sugar craving to a dysbiotic gut.