Dr. Will Bulsiewicz (Dr. B), a board-certified gastroenterologist and author of Fiber Fueled and The Fiber Fueled Cookbook, returns to discuss his new book Plant Powered Plus, which expands gut health into a holistic framework connecting mental, immunological, emotional, and spiritual health through the lens of inflammation and the gut microbiome.
Inflammation as the Root of Nearly All Modern Disease
Dr. B identifies inflammation as the single most important health challenge of our time, arguing that the vast majority of chronic conditions — from brain fog, headaches, and skin issues to autoimmune disease, metabolic dysfunction, hormonal imbalance, and mood disorders — share the same underlying driver.
He lists symptoms systematically from head to toe: difficulty concentrating, brain fog, headaches, nasal congestion, acne, eczema, psoriasis, bloating, constipation, diarrhea, acid reflux, urinary symptoms, erectile dysfunction, joint pain, chronic fatigue, insomnia, difficulty losing weight, blood sugar dysregulation, high blood pressure, and mood disturbances.
The number one symptom of inflammation is fatigue — feeling exhausted and never rested.
He argues that our modern lifestyle, which has shifted radically in the last 100 years, is fundamentally mismatched with our biology: we are indoors, sedentary, on screens 7 hours a day, eating ultra-processed foods, and socially isolated — none of which our grandparents experienced.
The Gut as the Body’s First Line of Defense
The gut microbiome (38 trillion microbes, mostly in the colon) is the body’s first line of defense; destroying it with antibiotics increases infection risk.
The second line is the gut barrier (lining); when it breaks down (“leaky gut” or increased intestinal permeability), substances cross into the bloodstream where 70% of the immune system resides.
The third line is the immune system itself — when activated, it produces inflammation.
Three most common disruptors of the gut microbiome: (1) ultra-processed foods, (2) disrupted circadian rhythm, and (3) chronic sympathetic nervous system activation from stress, loneliness, trauma, or lack of purpose.
The Brain-Gut Connection and the Autonomic Nervous System
The brain and gut are in constant two-way communication — “best friends” influencing each other continuously.
The sympathetic nervous system (adrenaline-driven: fight-or-flight) is designed for short bursts of survival energy, but modern life keeps people in sympathetic overdrive — from the moment they wake up and check their phones, through stressful jobs, unfulfilling work, and social media triggers.
The parasympathetic nervous system (rest-and-digest) is the opposite — activated by feeling safe, deep diaphragmatic breathing, human connection (holding hands, hugging, kissing), spiritual practices (prayer, scripture, singing hymns, religious services), and other intentional rest.
Chronic sympathetic overdrive sacrifices gut health: it disrupts the microbiome, breaks down the gut barrier, and activates inflammation.
Loneliness as a Physical Health Crisis
Over 50% of Americans reported feeling lonely before the pandemic; loneliness is on par with smoking 15 cigarettes per day in terms of health impact and mortality.
Humans evolved in tribes where family and community were the unit of survival — isolation was essentially a death sentence.
Modern culture has embraced individualism (proving self-worth independently, leaving family, not being dependent) and materialism (demonstrating value through possessions), both of which trade relationships for status and achievement.
Wealth has declined generationally, requiring more work to sustain lifestyles, further eroding time for connection.
Isolation keeps the body in a sympathetic state, driving inflammation and making people more prone to addictive coping mechanisms (scrolling, shopping, gambling, junk food).
Emotional Patterns, Trauma, and Disease
Dr. B’s mentor, Dr. Douglas Drossman at UNC, was a pioneer in merging psychiatry with gastroenterology, publishing in the 1990s on how trauma manifests as irritable bowel syndrome — work that was initially dismissed.
Trauma is defined broadly: anything that overwhelms a person’s ability to cope and leaves an imprint on the soul — not limited to abuse or childhood events.
Trauma stacks: each traumatic event raises the baseline, making future events more likely to be traumatic; significant losses bring up all previous losses.
Adopted children (before age 2) show higher rates of digestive problems, different gut microbiome patterns, and increased brain activity in trauma-associated regions on fMRI — even though they cannot consciously remember the event.
The body keeps the score: unprocessed emotional wounds manifest physically.
Spiritual Health as a Biological Necessity
Dr. B argues that science and faith are not mutually exclusive — the more he learns about the perfection of human physiology, the more convinced he is that it cannot be chance.
He proposes that every human civilization has independently concluded there is something greater — not the rational conclusion, but a persistent one.
Spiritual practice (broadly defined, not limited to organized religion) activates the parasympathetic nervous system: people with spiritual practices have significantly less substance abuse, better coping with illness, less depression and anxiety, lower blood pressure, fewer strokes, less heart disease, less Alzheimer’s, and live longer.
He is not proposing a “hack” but an honest inward choice: in a quiet moment, opening one’s heart to the possibility of something greater.
Even 10 minutes a day of spiritual practice (prayer, meditation, reading scripture, singing) can make a measurable difference.
He connects this to purpose: people who feel aligned with their purpose and connected to something larger feel safer, which biologically activates parasympathetic healing.
Dr. B’s Personal Story: Reconciliation with His Father
Dr. B came from a broken home — his parents divorced when he was 7, and the court system put him in the middle of a custody battle, creating a rift with his father that he blamed on him for decades.
He cut off his father completely from college through his 30s, driven by anger, low self-esteem, and a need to prove his worth through accomplishments.
His wife challenged him to reconcile; he called his father after more than 10 years, and his father welcomed him back instantly without resentment.
They had several good years together before his father died unexpectedly in January 2020.
Holding his newborn daughter helped him understand his father’s love — realizing the love he felt for her was the same love his father had always felt for him.
He had to forgive his father to heal himself — the key to the prison was with the prisoner.
The process of forgiveness is an opportunity for healing regardless of the other person’s response; it is a gift you give yourself.
After-Death Communication
After his father’s death, Dr. B’s friend Mark (who lost his own father young) warned him that his father would “reach out” to help him resolve things.
First incident: Two months after his father died, Dr. B appeared on a TV segment about a study showing COVID can present with GI symptoms (diarrhea) — the same symptom his father had before dying. The show displayed his name as “Bill Bulsiewicz” — his father’s name, not his (Will) — and later corrected it without being asked. This helped him process that his father likely died of COVID.
Second incident: Dr. B felt compelled to watch a 1984 Syracuse vs. Georgetown basketball game on YouTube — a game he had no memory of watching. The game ended with a legendary half-court shot by Syracuse player Raf Washington. The next day he called his brother, who was settling their father’s estate, and learned that a photograph of that exact shot was on their father’s refrigerator, three feet away.
Dr. B interprets these as genuine communication from his father, though he acknowledges alternative explanations (unconscious memory, synchronicity) — ultimately it is a matter of faith.
He believes he will be with his father again after his own death, and that his children will be with him.
GLP-1 Drugs: Benefits, Risks, and Long-Term Concerns
GLP-1 agonists (like Ozempic/Wegovy) are genuinely lifesaving for people with obesity and diabetes — Dr. B is glad they exist for those who need them.
However, he is concerned about the broader cultural approach: rather than examining the lifestyle and diet that caused the health crisis, the solution is to take a drug while maintaining the same lifestyle.
He draws a parallel to proton pump inhibitors (PPIs) like Nexium, which were prescribed for acid reflux for years with the belief they had no side effects — until studies emerged linking them to dementia, chronic kidney disease, and cardiovascular risk. The mechanism: stomach acid keeps the microbiome in balance; suppressing it causes small intestinal bacterial overgrowth (SIBO), which connects to systemic inflammation.
GLP-1s have known side effects, and the long-term effects of 30-70 years of use are unknown.
When the drug is stopped, weight returns — people describe being unable to control their hunger.
The drug companies will never fund the study that matters: how to put someone on the drug while changing diet and lifestyle, then remove the drug while maintaining weight loss — because lifetime use is the business model.
He is concerned about children and healthy-weight adults (size 8-10) being put on these drugs.
Caloric restriction without dietary change leads to nutritional deficiencies — especially fiber deficiency (95% of Americans are already deficient) and protein deficiency.
“Ozempic face” reflects muscle loss, which is especially concerning for postmenopausal women already losing estrogen that supports muscle mass.
Protein: How Much Do We Actually Need?
The recommended minimum is 0.8 g/kg of body weight; Dr. B recommends 1.2-1.6 g/kg for most people (closer to 1.6 on workout days, 1.2 on rest days).
The internet trend of 1 gram per pound of body weight (2.2 g/kg) is nearly triple the minimum and forces people toward animal protein or supplements.
Protein is the muscle nutrient; fiber is the longevity nutrient.
All plant-based foods contain protein; Dr. B (who does not eat meat) lifts the heaviest weights of his life at 45.
His primary protein source: beans, which also provide fiber, resistant starches, and polyphenols.
The obsession with meat protein is driven partly by the “manosphere” and internet culture, and it pushes people away from plant-based foods they desperately need for fiber.
Fiber: The Longevity Nutrient
95% of Americans are fiber deficient. Women average 15g/day (should be 25g); men average 18g/day (should be 38g).
Fiber feeds gut microbes to produce short-chain fatty acids (acetate, propionate, butyrate) — the most anti-inflammatory substances in the body.
Short-chain fatty acids restore the gut barrier, suppress inflammation, produce regulatory T cells (immune peacekeepers), and heal the entire body including the brain and blood-brain barrier.
Fiber deficiency means missing these benefits, contributing to systemic inflammation.
Debunking Carnivore and Sardine-Only Diets
Any diet that tells you to eat only one food is a setup for failure — no single food is complete, and overconsuming anything becomes problematic (even oxygen, water, and salt can be toxic in excess).
Sardines contain beneficial omega-3s, but eating only them means excessive omega-3s and exposure to mercury and nanoplastics concentrated in fish.
Dietary variety allows the strengths of different foods to complement each other and addresses individual deficiencies.
The argument for sardine-only or carnivore diets is really about forcing the body into ketosis.
Ketosis Explained
In ketosis, the body produces ketone bodies (beta-hydroxybutyrate and acetoacetate) as an alternative fuel when carbohydrates are absent.
These ketone bodies work at the same receptors as short-chain fatty acids (from fiber) but are like a “messed up key” — they partially enter the lock and give a partial effect.
The body produces ketones precisely because short-chain fatty acids are so important — ketosis is the backup system when fiber is absent.
Compared to the standard Western diet (loaded with sugar, junk fat, and no fiber), ketosis is better because it at least provides a crude version of these beneficial compounds.
But a whole-food, fiber-rich diet provides the full, optimal version — making ketosis unnecessary.
This also explains why fasting helps people: not because abstaining from food is inherently beneficial, but because it gives the gut a break from inflammatory ultra-processed food. If you were eating whole nutritious food, fasting would not provide the same benefit.
The Problem with Ultra-Processed Fast Food
A typical fast food meal (burger, fries, diet Coke) causes blood sugar to spike (eroding the gut barrier), triglycerides to rise (peaking at 6 hours, driving inflammation), and the gut to enter an inflammatory state for 6-8 hours.
Alcohol also drives triglycerides up hard.
If another meal is consumed during this window, inflammation compounds; if a break of 12-14 hours is given, the gut enters repair mode.
This is the mechanism behind time-restricted eating benefits — the gut microbiome starts showing benefits at 12 hours, with further improvement at 14 hours (as shown in a Zoe study of 40,000 people who reported more energy, less hunger after initial adaptation, and less bloating).
Important caveat: Fasting is not for everyone — contraindicated for those with disordered eating (anorexia, bulimia, restrictive tendencies), autoimmune conditions, or adrenal burnout.
Circadian Rhythm and the Gut
About half of human genes are turned on and off at specific times during a 24-hour cycle.
Over 50% of gut microbes rise and fall at specific times to serve the body’s needs.
During the day, microbes are geared toward protein metabolism (supporting physical activity); at night, they shift to rest, recovery, and gut barrier repair.
The immune system is nocturnal — congestion, coughs, soreness, and inflammation worsen at night because the immune system is actively working while you sleep.
An active immune system during the day causes fatigue and low energy; at night it serves repair.
Consistent meal timing matters — the body and microbiome expect regularity, much like toddlers who become distressed when meals are at irregular times.
The Bigger Picture: Healing Requires Addressing the Whole Person
Dr. B sees his books as tools for healing — each one designed so that a specific person can find what they need.
He wrote Plant Powered Plus because he sees pain and loneliness everywhere, and addressing these is healing — not “woo-woo” but grounded in the physiology of the brain-gut connection.
Health is not just about food — it is about when you eat, how you eat, why you eat, and how you feel about yourself, the universe, and something greater than yourself.
The book builds toward a protocol in the back, but the deeper message is that no protocol works if the emotional and spiritual dimensions are ignored.
He encourages people to find their own path toward healing — through therapy, quiet reflection, community, spiritual practice, or simply opening the heart in a quiet moment.
