The Gravity Doctors

Lachlan Kent
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  • MEDICINE
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Dr Brennan Spiegel and Dr Lachlan Kent introduce you to the world of Biogravitational Medicine, how gravity shapes our bodies and minds for better or worse. Explore the principles of gravity management, how you can improve your gravity resilience, and what to do when gravity fails you and your body. Dr Spiegel is a trained M.D., professor of public health at Cedars-Sinai hospital in LA, and author of the book 'Pull - How gravity shapes your body, steadies the mind, and guides our health'. Dr Kent is a cognitive scientist with a PhD in the psychology of 'mental gravity'.

Episodes

  1. 20/12/2025

    Serotonin: The Body’s Anti-Gravity Molecule - Ep 8

    Dr Brennan Spiegel (physician, gastroenterologist, and author of Pull) and Dr Lachlan Kent (cognitive scientist and founder of Mental Gravity) explore serotonin as a gravity-management molecule, reframing it not simply as a “happiness chemical,” but as a fundamental biological system that allows life to stand up, move fluids, regulate balance, and remain psychologically buoyant in a gravitational field. Together, Brennan and Lachlan unpack new research on serotonin’s role across the gut, cardiovascular system, lymphatics, vestibular system, reproduction, and mood—showing how 95% of serotonin is produced in the gut, in symbiosis with the microbiome. They trace serotonin’s evolutionary origins from ocean life to land, altitude, and even space, and discuss practical implications for diet, exercise, sunlight, microbiome care, and mental health. 1. What Is Serotonin? A whole-body gravity resilience molecule, not just a brainneurotransmitter Exists in two largely separate compartments: brain and gutCentral to movement, circulation, balance, mood, and vitalityEvolutionarily conserved across plants, animals, and humans Serotonin as a Gravity-Management System Gut & DigestionMotility against gravity in any body orientation Pumps & TubesBlood pressure regulation, cardiac contractility, lymphatic return Balance& OrientationVestibular function; dizziness during SSRI withdrawal ReproductionRetrograde uterine contractions that move sperm upward against gravity Mood &EnergyMental elevation, vitality, resilience, and time perception The Microbiome–Serotonin Alliance Trillionsof microbes are required to trigger serotonin productionThe gut as a “dark, sulfurous, hydrothermal” evolutionary nicheA symbiotic bargain: microbes get mobility; humans get serotoninChanges in altitude, microgravity, and spaceflight rapidly alter serotoninbiology STACK TEN: The Anti-Gravity Diet (introduced) A practical framework from Pull for supporting serotonin production via tryptophan-rich foods. Core principles:Tryptophan as substrateMicrobiome diversityDietary balance rather than supplementation alone Therapeutic & Self-Care Implications Dietary modification (tryptophan-rich foods, microbiome-supportive diets)Exercise and movementSunlight and time outdoorsWorking with dietitians for GI and mood conditions (e.g., low-FODMAP when indicated)Understanding limits and side effects of SSRIsNaturally supporting serotonin across body and mind Metaphor & Meaning The gutmicrobiome as the “spice factory” of human biologySerotonin as the true “spice of life”—powerful, regulating, and double-edgedGravity as the organizing principle linking biology, psychology, and medicine Timecodes 00:00 —Welcome & why serotonin matters01:10 — Serotonin beyond the “happiness chemical”02:20 — Gut vs brain serotonin compartments03:20 — Pumps, tubes & whole-body effects04:25 — Lymphatics, reproduction & balance06:20 — Evolutionary origins & gravitation08:10 — Microbiome symbiosis metaphor10:15 — Altitude, spaceflight & serotonin disruption11:30 — STACK TEN diet introduced12:45 — Diet, microbiome & mood disorders13:50 — Dune, spice & serotonin metaphor15:45 — SSRIs: benefits, limits & side effects17:00 — Natural serotonin support & integration17:45 — Closing reflections & next steps Resources The Gravity Doctors website: https://thegravitydoctors.comDr Brennan Spiegel: https://brennanspiegelmd.comDr Lachlan Kent: https://lachlankent.auBook — Pull: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health

    18 min

  2. 08/12/2025

    Brennan's antigravity diet - Boost your serotonin with STACK TEN Ep 7

    Dr Brennan Spiegel (physician, gastroenterologist, and author of Pull) and Dr Lachlan Kent (cognitive scientist and founder of Mental Gravity) explore how diet, microbiome diversity, and serotonin production shape your capacity to stand up to gravity—physically and mentally. They introduce the Anti-Gravity Diet and Brennan’s STACK TEN framework, a simple, evidence-informed way to support the gut’s serotonin “factories” and improve whole-body gravity resilience. Along the way, they unpack how food, fibre, omega-3s, polyphenols, vagus-nerve activation, and mindful rest all participate in the body–mind system that keeps us upright and energised. Together, Brennan and Lachlan discuss babies as “gravity novices,” leaky gut, the gut–brain axis, evolutionary embodiment, time dilation in depression, and why serotonin—serum tone—is essential for managing the constant downward pull of Earth’s gravity. A holistic framework for supporting natural serotonin production—the body’s anti-gravity molecule.Grounded in gastrointestinal physiology, microbiome science, and biogravitational medicine. Not a restrictive diet — a practical, everyday toolkit for gravity resilience.A memory device for foods that supply the raw material (tryptophan) for serotonin production: SalmonTurkeyAvocadoChickpeasKidney beansTofu/TempehEggsNuts Paired with: Fibre → feeds microbes that create short-chain fatty acids Omega-3s → shift the microbiome toward serotonin-supporting species Polyphenols → found in berries, cocoa, turmeric, and green tea 00:00 — Welcome & overview of the Anti-Gravity Diet01:20 — Serotonin as the body’s anti-gravity molecule04:20 — Microbiome diversity & the gut barrier06:30 — Babies, serotonin & early gravity resilience09:40 — Tryptophan, fibre & short-chain fatty acids11:00 — Leaky gut, inflammation & decoherence13:00 — Food–mood science & depression16:40 — What to eat: introducing STACK TEN17:00 — The ten tryptophan-rich foods18:50 — Polyphenols, omega-3s & microbiome tuning19:50 — Beyond diet: exercise, nature, sunlight21:20 — Balancing sympathetic vs parasympathetic tone23:00 — Vagus-nerve stimulation & rest-and-digest24:30 — Gravity as the integrator across biological levels26:00 — Life as a system for managing gravity27:20 — Closing reflections & future topics The Gravity Doctors website: ⁠https://thegravitydoctors.com⁠Gravitype Quiz: virtualmedicine.org/pullDr Brennan Spiegel: brennanspiegelmd.comDr Lachlan Kent: lachlankent.auBook — Pull: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health

    28 min

  3. 01/12/2025

    What's your Gravitype? Take the quiz to find out Ep 6

    In this episode, Dr Brennan Spiegel (physician, gastroenterologist, and author of Pull) and Dr Lachlan Kent (cognitive scientist and founder of Mental Gravity) dive deep into gravity resilience and introduce listeners to the new Gravitype Quiz—a wellness tool that blends biomechanics, neuroscience, and psychology to help people understand their personal relationship with gravity. Together, Brennan and Lachlan take the quiz live on the show and compare results, unpacking the three pillars of biogravitational health: gravity fortitude, gravity sensing, and mental gravity. Along the way, they explore back pain, dizziness, cold exposure, resilience, interoception, emotional balance, and how experiences like roller coasters or elevators reveal something about your gravitational tendencies. You can try the full interactive quiz here: brennanspiegelmd.com virtualmedicine.org/pull thegravitydoctors.com 1. What Is a Gravitype? A personalised profile of gravity resilience Based on the framework in Pull and grounded in emerging concepts in biogravitational medicine Not a diagnostic tool — currently evidence-informed and intended for education/wellness Gravity Fortitude Muscles, bones, pumps, and tubes Cardiovascular and postural strength Back pain, leg swelling, stair climbing, grip strength Gravity Sensing Inner ear, proprioception, vestibular function Balance tests (like one-leg standing) Cold sensitivity, interoception, dizziness/vertigo Mental Gravity Weighted-down vs uplifted Stress tolerance, emotional recovery, “flow” states Dual-continuum model of mental health Grip strength as a predictor of longevity BMI and physical load on the spine Orthostatic light-headedness and blood pressure regulation Inner-ear disorders (e.g., BPPV) and sensory hypersensitivity The anterior insula as the “gravity conductor” of the body–mind symphony They answer questions on: Opening a jar Climbing stairs Back pain Light-headedness Balance Cold tolerance Emotional reactivity and resilience Roller coaster sensitivity Positive emotional absorption (flow) Each reflects personally on past injuries, thyroid health, yoga, meditation, diet, travel, and evolving gravitational resilience across their lives. Durable fortitude Normosensitive sensing Lifted mental gravity Notes how training (cold exposure, yoga, flying) reshaped Lachlan's sensitivity over time. Reflections on vertigo, cold intolerance, and emotional uplift as part of Brennan's profile. Both discuss how gravitypes can change with training, awareness, and targeted practices. Examples include: Down-regulating sensory overload (slow nasal breathing, longer exhales, box breathing) Strengthening the gravity fortitude system (movement, posture, reducing sitting time) Noticing “watch-outs” such as back pain, dizziness, or emotional rumination Links included in the show notes. 00:00 — Welcome, origins of the gravitype 01:30 — Gravity resilience basics 03:00 — Gravity fortitude (muscles, tubes, pumps) 06:45 — Mental gravity explained 08:00 — Starting the quiz 09:00 — Grip strength & longevity 11:00 — Stair climbing & cardiovascular load 12:00 — Back pain & evolution 15:00 — Orthostatic dizziness & fainting 18:00 — BMI, weight, and gravitational load 20:00 — Leg swelling, pumps & tubes 23:30 — Gravity sensing & vertigo 25:00 — Balance tests (one-leg stance) 26:30 — Cold sensitivity & nervous-system tuning 29:30 — Interoception & the anterior insula 33:00 — Stress, heaviness & mental gravity 36:00 — Roller coasters, turbulence & fear responses 38:00 — Emotional resilience and bouncing back 41:00 — Flow states and uplift 43:00 — Revealing their gravitypes 46:30 — What their results mean 48:00 — Final reflections & where to take the quiz The Gravity Doctors website: https://thegravitydoctors.com Gravitype Quiz: available on BrennanSpeigelMD.com & virtualmedicine.org Dr Brennan Spiegel: brennanspiegelmd.com Dr Lachlan Kent: lachlankent.au Book — Pull: How Gravity Shapes Your Body, Steadies the Mind, and Guides Our Health

    50 min

  4. 03/11/2025

    Mental Gravity: The hidden force shaping your mind and emotions - Ep 5

    Dr. Brennan Spiegel (Cedars-Sinai) and Dr. Lachlan Kent explore how gravity shapes not only our bodies but our minds. Through the lens of Cathy Freeman’s gold-medal run, they discuss mental gravity — the feeling of emotional “weight” and lightness that defines human experience. From Einstein’s relativity to embodied cognition and Cedars-Sinai’s virtual-reality therapy, they connect physics, psychology, and physiology to show how alignment with gravity may be the key to wellbeing. Topics include depression as a “mental gravity well,” glucose and perception, VR and levity, and how mindfulness, diet, and physical balance can help us stay buoyant in heavy times. Key themes: Mental Gravity: The experience of emotional and cognitive “weight,” shaped by our alignment with the physical world’s gravitational pull. Embodied Cognition: How bodily states and forces (like gravity, glucose, or posture) shape perception and thought.Gravity Intolerance: A unifying framework for disorders where physical and mental balance are disrupted. Mind over Matter: Using imagery, mindfulness, and movement to generate upward momentum and emotional lightness.Timecodes: 00:00 – 01:30 | Welcome to The Gravity DoctorsIntroducing Brennan and Lachlan; overview of physical and mental gravity. 01:30 – 03:50 | The Cathy Freeman StoryHow Cathy transcended the “weight of expectation” to run with joy and lightness — an example of mental gravity at its best. 03:50 – 06:00 | The Weight of EmotionExploring why positive emotions feel light and negative emotions feel heavy — from embodied metaphors to physical postures of depression. 06:00 – 08:10 | Embodied Cognition and Glucose StudiesBrennan cites research showing blood-glucose levels alter perception of hill steepness — a literal bridge between physiology and perception. 08:10 – 11:00 | The Birth of the Theory of Mental GravityLachlan recalls his “aha” moment linking Einstein’s general relativity lecture on black holes to psychological depression — both described using the same language of heaviness, collapse, and isolation. 11:00 – 12:40 | Gravity Wells, Black Holes, and RecoveryComparing mental “gravity wells” to depression — but unlike black holes, people can pull themselves out. 12:40 – 16:20 | Champagne, Joy, and the Physics of EmotionWhy celebration rituals mirror gravitational metaphors — bubbles rising, buoyancy, and the inevitable “come-down.” 16:20 – 19:30 | Virtual Reality as a Gravity-Hacking ToolCedars-Sinai research: VR experiences that simulate floating or flying reduce pain, anxiety, and inflammation — measurable physiological effects of simulated levity. 19:30 – 22:00 | Mindfulness and Mental ImageryUsing mental imagery and meditation to reshape the brain-body landscape and foster feelings of lightness and alignment. 22:00 – 25:50 | The Continuum of Mind and BodyWhy mind and body aren’t separate but part of one continuous system — like a cross-country landscape shifting seamlessly from desert to sea. 25:50 – 28:30 | Gravity Intolerance and Health ResilienceReframing conditions like IBS, POTS, and anxiety as variations of gravity intolerance; maintaining physical and mental balance as the essence of wellbeing. 28:30 – 30:00 | Everyday Applications & Closing ReflectionsFrom mindfulness to serotonin-rich diets and time in nature — practical tools to stay buoyant. Final reflections on finding balance between empowerment and medical treatment. Want to discover your 'Gravitype'? Visit The Gravity Doctors website:https://thegravitydoctors.com/ Order Brennan's book "Pull" to learn more about how gravity shapes your health in both body and mind via his personal ⁠⁠personal website⁠⁠: https://www.brennanspiegelmd.com/pull Visit ⁠⁠Lachlan's website ⁠⁠to learn more about his work in mental gravity: https://lachlankent.au/ Music by ⁠ALLIRA⁠ and Visceral Sound - https://www.youtube.com/@ALLIRAmusic Recording at ⁠JTB Studio⁠ by David Iskandaryan.

    31 min

  5. 13/10/2025

    Harnessing gravity to overcome chronic illness w/ Harmon Clarke - Ep 4

    In this uplifting and deeply human episode of The Gravity Doctors, Dr. Brennan Spiegel (Cedars-Sinai gastroenterologist and author of PULL) and Dr. Lachlan Kent (cognitive scientist and theorist of Mental Gravity) sit down with Harmon Clarke, a patient-turned-researcher whose remarkable recovery story illuminates the future of biogravitational medicine. From septic shock and 200 days in hospital to yoga teacher, breathwork practitioner, and health researcher, Harmon’s journey embodies resilience, creativity, and the healing power of re-engaging with gravity. Together, they explore how movement, inversions, virtual reality, and breathwork can transform pain and depression into buoyancy and balance — culminating in a spontaneous “Gravity Rap” that captures the spirit of the show. Core Themes Gravity as a unifying metaphor for physical and mental health Movement and inversion therapy for resilience and recovery Virtual reality and embodied cognition Tensegrity, balance, and the biomechanics of wellbeing Patient empowerment and the hero’s journey in healing Biogravitational medicine as a synthesis of East–West paradigms 00:00 – Welcome and Introductions 01:00 – Facing the Grave 03:00 – Virtual Reality and the Mind–Body Connection 06:00 – Yoga, Breathwork, and Natural Recovery 08:00 – The Science of Inversion and Tensegrity 14:00 – Hospitals and Gravity Intolerance 18:00 – Depression as a Gravitational Condition 24:00 – Cathy Freeman and Gravitational Flow 25:45 – East Meets West 30:00 – Rebalancing Medicine 33:00 – The Simple Tools of Healing 35:00 – Designing the Future of Biogravitational Medicine 38:00 – Generational Health and Modern Comfort 41:00 – The Gravity Rap Finale Order Brennan's book "Pull" to learn more about how gravity shapes your health in both body and mind via his personal ⁠⁠personal website⁠⁠. Visit ⁠⁠Lachlan's website ⁠⁠to learn more about his work in mental gravity. Music by ⁠ALLIRA⁠ and Visceral Sound Recording at JTB Studio by David Iskandaryan. Editing by Dr Karisma Suchak.

    46 min

  6. 30/09/2025

    Top 10 Gravity Tips - Ep 3

    Biogravitational Medicine is a holistic approach to maintaining health in both body and mind. It's like a toolkit where you can find what works for you and your particular situation. Here are our top ten that work for most people most of the time. (As always, consult a doctor for personalised medical advice before attempting anything that might pose a risk to your physical or mental health, or for treatment of acute or chronic conditions. The information here is for educational and information purposes only.) Order Brennan's book "Pull" to learn more about how gravity shapes your health in both body and mind via his personal ⁠personal website⁠. Visit ⁠Lachlan's website ⁠to learn more about his work in mental gravity. Music by ALLIRA and Visceral Sound This episode was recorded at ⁠Myst Music⁠. Audio engineering by Jeremy Roberts. Audio and video editing by Dr Karisma Suchak.

    35 min

  7. 11/09/2025

    'Pull' book preview - Ep 2

    Dr Spiegel has written a book about gravitational health called 'Pull' on the wide ranging themes underpinning this podcast - gut health, mental gravity, serotonin, the inner ear, the body's pumps and tubes, the gravitostat, and many more. The hosts take a tour through the world of biogravitational medicine by telling the story of what inspired the book, where the science is heading, and how people can apply the principles in their daily lives. Order Brennan's book "Pull" to learn more about how gravity shapes your health in both body and mind via his personal personal website. Visit Lachlan's website to learn more about his work in mental gravity. Music by ALLIRA and Visceral Sound. This episode was recorded at Myst Music. Thanks to Jeremy Roberts for audio engineering and Dr Karisma Suchak for editing.

    25 min

  8. 09/09/2025

    Gut Feelings: The gravitational roots of the mind-body connection - Ep 1

    You know the feeling you get in your belly when falling on a rollercoaster? Ever wondered why we get similar gut feelings when we're "falling" in love?  In this episode, Brennan (a gastroenterologist) and Lachlan (a cognitive scientist) talk about how gravity shapes gastrointestinal function and what relation gut feelings have to physical and mental health. They discuss Brennan's viral scientific paper, "Gravity and the Gut: A Hypothesis of Irritable Bowel Syndrome" and Lachlan's breakthrough theory of the mind called "Mental Gravity", and the connections between their shared ideas. Conditions like IBS often lead to anxiety and depression, which are the mental equivalent of "falling" and having "fallen", and so they draw a connection between gut health, gut feelings, and mental health. Strap yourself in for a rollercoaster ride through the topsy-turvy world of gut feelings in both body and mind. Order Brennan's book "Pull" to learn more about how gravity shapes your health in both body and mind via his personal personal website. Visit Lachlan's website to learn more about his work in mental gravity. Music by ALLIRA and Visceral Sound. This episode was recorded at ⁠Myst Music⁠. Thanks to Jeremy Roberts for audio engineering.

    28 min
  • 8 Episodes

About

Dr Brennan Spiegel and Dr Lachlan Kent introduce you to the world of Biogravitational Medicine, how gravity shapes our bodies and minds for better or worse. Explore the principles of gravity management, how you can improve your gravity resilience, and what to do when gravity fails you and your body. Dr Spiegel is a trained M.D., professor of public health at Cedars-Sinai hospital in LA, and author of the book 'Pull - How gravity shapes your body, steadies the mind, and guides our health'. Dr Kent is a cognitive scientist with a PhD in the psychology of 'mental gravity'.

Information

  • Creator
    Lachlan Kent
  • Years Active
    2K
  • Episodes
    8
  • Rating
    Clean
  • Copyright
    © Lachlan Kent
  • Show Website
    The Gravity Doctors

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