The Peter Attia Drive

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In this episode, Peter welcomes back Dr. Siddhartha Mukherjee, a physician, oncologist, researcher, and the Pulitzer Prize-winning author of The Emperor of All Maladies. Fifteen years after the book was first published, Sid released an updated edition. This conversation examines what has changed in our understanding of cancer—not only in how we treat it, but in how we think about its causes, prevention, detection, and biology. Sid explores the contributions of genetics, environmental exposures, random mutations, and inflammation to cancer risk, including the emerging role of hyperinsulinemia and metabolism. He discusses why detecting cancer early remains so difficult, particularly in pancreatic cancer, and how advances in immunotherapy, CAR T cell therapy, and targeted treatments such as KRAS inhibitors are changing the treatment landscape. The conversation then broadens beyond cancer to what Sid calls "regenerative failure"—the declining ability of tissues to repair and replenish themselves with age. Peter and Sid explore how this process may contribute to conditions such as osteoarthritis, and whether longevity should be approached less as the prevention of individual diseases and more as the preservation of regenerative capacity. Sid weighs in on the potential for chemoprevention, metabolic interventions, and AI to transform cancer prevention and treatment. Finally, they discuss what it would take to develop meaningful biomarkers of longevity that could ultimately help to extend human healthspan and lifespan.
We discuss:
What oncology has learned in the 15 years since The Emperor of All Maladies was published [2:45];
The contributions of genetic risk, bad luck, and inflammation to cancer [14:45];
The role of metabolism and hyperinsulinemia in cancer [31:00];
Osteoarthritis: the role of inflammation and regenerative stem cells [40:45];
How cancer escapes the immune system—the subtleties of neoantigens and immune checkpoints [49:45];
AI and the thymus as a predictor of longevity, and T cell aging and immune regeneration [57:15];
How CAR T cell therapy works and why solid tumors are harder to treat [1:04:00];
Targeting KRAS in pancreatic cancer [1:10:45];
The rise of colorectal cancer in younger adults [1:19:15];
How AI may transform drug discovery [1:23:00];
The future of cancer prevention: chemoprevention [1:33:15];
Challenging the current model of longevity—disease prevention versus targeting regenerative failure [1:37:45];
The need for a biomarker of longevity—comparing geroscience to atherosclerosis [1:50:30];
Clinical trials targeting cancer metabolism [1:56:00];
What Sid is currently writing about and a glimpse into his writing process [1:58:00]; and
More.
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In this "Ask Me Anything" (AMA) episode, Peter looks back on 400 episodes of The Drive with another installment of "strong convictions, loosely held," revisiting some of the positions he has taken over more than eight years of the podcast. He explains why changing one's mind in response to new evidence, conversations with experts, and clinical experience is essential for practicing medicine well. Peter begins with nutrition, describing how his views on ketogenic diets, extended fasting, and the framework of dietary restriction, time restriction, and calorie restriction have evolved. He explains why he no longer takes metformin for longevity and discusses his growing uncertainty around rapamycin despite compelling animal data. Peter also revisits his views on cancer screening, including whole-body MRI and liquid biopsies for early detection. On exercise, Peter explains how his approach to cardiorespiratory training and the 80/20 Zone 2 framework has changed, particularly for people with limited time to train. He also shares why he has moved away from heavy barbell squats and deadlifts and how he now thinks about balancing benefit and injury risk. Throughout the episode, Peter emphasizes the importance of focusing on durable principles, strong foundations, and sustainable practices rather than chasing optimizations that provide marginal gains.
If you're not a subscriber and are listening on a podcast player, you'll only be able to hear a preview of the AMA. If you're a subscriber, you can now listen to this full episode on your private RSS feed or our website at the AMA #90 show notes page. If you are not a subscriber, you can learn more about the subscriber benefits here.
We discuss:
Strong convictions, loosely held: changing opinions as evidence, expert conversations, and clinical experience evolve [2:00];
Nutrition: Peter's evolving view of ketogenic diets, energy balance, and dietary dogmatism [5:30];
Extended fasting, autophagy, lean-mass loss, and who may benefit from prolonged fasting [12:00];
The dietary restriction, time restriction, and calorie restriction framework—and why GLP-1 agonists are tipping the balance toward calorie restriction [20:15];
Why Peter no longer views metformin as geroprotective for metabolically healthy people [24:45];
Rapamycin for longevity: compelling animal data, unresolved human dosing, and Peter's growing uncertainty [29:15];
The importance of early cancer detection, declining whole-body magnetic resonance imaging (MRI) quality, and more targeted alternatives [41:30];
Liquid biopsies for cancer screening: the NHS-Galleri trial, why early-stage rather than late-stage detection is what actually matters, and why the technology remains "fuzzy" [53:30];
Evolving exercise goals, the limitations of the 80/20 Zone 2 framework, and programming cardio at lower training volumes [1:00:00];
Exercise prescriptions for limited time, building a training habit, and becoming less dogmatic about forcing workouts [1:05:00];
Moving away from heavy squats and deadlifts, alternative exercises, and deliberate risk management [1:13:00];
Prioritizing principles, foundations, and sustainable practices over marginal optimization [1:21:30]; and
More.
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In this episode, Peter sits down with Dr. Kathryn (Katie) Gray, a physician-scientist, high-risk obstetrician, and maternal-fetal medicine specialist at the University of Washington School of Medicine. Katie begins by explaining the remarkable physiologic changes that occur during pregnancy and how the cardiovascular, metabolic, and hormonal systems adapt to support both mother and developing fetus. From there, the conversation turns to some of the most important complications that can arise. Katie explains how gestational diabetes is screened for and treated, and what a diagnosis may mean for the long-term health of both mother and child. She then walks through the biology of preeclampsia, including who is at risk and how the condition is managed. She also discusses HELLP syndrome and postpartum depression. Peter and Katie explore the realities of labor and delivery, including breech presentation, the role of midwives, and the trade-offs between vaginal and cesarean delivery. The conversation also covers stillbirth and the growing role of cell-free DNA in prenatal genetic screening. Other topics include prenatal nutrition and folate, breastfeeding, and exercise during pregnancy. Throughout the episode, Peter and Katie return to a larger question: What can pregnancy reveal about a woman's long-term health? They discuss how complications during pregnancy can provide important clues about future health risks. Finally, Katie highlights some of the major questions that remain unanswered in maternal health and why greater investment in research is needed to improve outcomes for mothers and their children.
Disclaimer: The views expressed on this podcast are solely those of Dr. Kathryn Gray and do not represent the University of Washington or any of its affiliated units. Dr. Gray speaks solely in a personal capacity, and nothing here should be construed as an official position or endorsement from the University of Washington.
We discuss:
What drew Katie to obstetrics and gynecology, and fundamental questions in the field that remain unanswered [3:15];
Pregnancy as a cardiovascular and metabolic stress test; the first symptoms and early changes [6:30];
Early hormonal changes, prenatal nutrition, and neural tube defects [16:00];
Fetal development and the physiology of gestational diabetes [23:45];
Diagnosing and treating gestational diabetes [30:00];
Preeclampsia: diagnosis, biology, acute risk, and how it's managed [37:00];
HELLP syndrome, what genetic studies reveal about preeclampsia, and the antihypertensive medications used to treat it [49:00];
What pregnancy reveals about long-term cardiometabolic health [54:45];
Cesarean delivery, breech presentation, and stillbirth [1:01:15];
The onset of labor, cervical dilation, and membrane rupture [1:14:15];
Vaginal delivery and breastfeeding: benefits versus myths [1:23:15];
Exercise during pregnancy, sleep position in the third trimester, and postpartum depression [1:27:00];
Prenatal genetic screening: the growing role of cell-free DNA and the gap between what is technologically possible and what gets deployed in the clinic [1:33:00];
Midwifery and the realities of childbirth [1:39:00];
Maternal health in the United States and the need for research investment [1:48:30]; and
More.
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Lloyd B. Klickstein is a physician-scientist who has spent more than 20 years at the intersection of drug discovery, healthy aging, and preventive medicine. Drawing on his experience in academic medicine, translational research, and biotechnology, Lloyd walks through the full arc of modern drug development. He explains how scientists identify an unmet medical need and decide which diseases and therapeutic targets are worth pursuing. From there, he takes us through the process of engineering a drug, testing it in animals, and navigating clinical trials and regulatory approval. Using bimagrumab as a case study, Lloyd explains the rationale for targeting myostatin and activin signaling to increase muscle mass and strength and describes how the antibody was engineered and screened. He then walks through what was learned from early clinical trials. Unexpected effects on fat mass and type 2 diabetes helped reshape bimagrumab's development as a potential treatment for obesity, including its use in combination with semaglutide. Along the way, Peter and Lloyd explore the differences among drug modalities, including biologics and small-molecule therapeutics. They discuss the roles of patents and capital allocation in drug development, along with the requirements for IND submission and GMP manufacturing. They also examine why developing a new drug takes so long and costs so much, and why identifying failures early is critical. At the end of the episode, the conversation turns to mTOR inhibition and geroprotection, as well as Lloyd's current work on a novel pharmacologic approach to cancer prevention. This episode provides a rare behind-the-scenes look at how new medicines are actually created and the scientific, regulatory, and economic decisions that determine which ideas ultimately make it to patients.
We discuss:
Lloyd's path from academic medicine to translational drug development [3:15];
Drug modalities, patents, and the economics of innovation [11:30];
Choosing sarcopenia as a target for drug development, and confronting the problem of measuring falls [23:00];
The rationale for bimagrumab: improving muscle mass and strength by targeting myostatin and activin signaling (and why follistatin failed) [36:45];
Engineering and screening the bimagrumab antibody, and the cost of developing a new drug [43:45];
From candidate antibodies to animal proof of concept (impressive muscle hypertrophy) [54:15];
Toxicology, capital allocation, and the path to an IND [1:02:45];
IND requirements, GMP manufacturing, and gray market peptides [1:14:45];
First in-human study design, patient selection, and protection of healthy volunteers [1:22:00];
Phase 1 dosing, pharmacodynamics, and global trial strategy [1:33:45];
Phase 2 lessons on muscle mass, function, and nutrition [1:43:30];
Bimagrumab's effects on fat mass and type 2 diabetes [1:50:45];
The BELIEVE trial of bimagrumab plus semaglutide [1:59:30];
Selective mTORC1 inhibition and the challenge of testing geroprotection [2:11:45];
A new pharmacologic approach to cancer prevention [2:15:45]; and
More.
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In this "Ask Me Anything" (AMA) episode, Peter takes a deep dive into thyroid health and explains why diagnosing and managing thyroid dysfunction is unusually complex. He begins with the basic biology of the thyroid gland and three commonly measured hormones—free T4, free T3, and TSH. He explains how T4 is converted to the active hormone T3 and the important functions T3 performs throughout the body. He also explains what reverse T3 is and when it may be useful to measure it. Peter then breaks down thyroid blood tests and their limitations and provides a practical framework for evaluating suspected thyroid dysfunction. He explains why symptoms alone are insufficient for diagnosis and reviews the criteria for diagnosing hypothyroidism, along with conditions that can mimic it. He also explores how hypothyroidism can be both underdiagnosed and overtreated and how to navigate subclinical hypothyroidism. Peter discusses treatment with T4 and T3, including why some patients continue to experience symptoms despite standard T4 replacement. He also explains how thyroid medications should be taken to optimize absorption. Additional topics include Hashimoto's disease, thyroid considerations during pregnancy, hyperthyroidism, the risks of excess iodine, and supplements marketed to support thyroid function. Finally, Peter offers guidance for patients who continue to feel unwell despite apparently normal thyroid tests.
If you're not a subscriber and are listening on a podcast player, you'll only be able to hear a preview of the AMA. If you're a subscriber, you can now listen to this full episode on your private RSS feed or our website at the AMA #89 show notes page. If you are not a subscriber, you can learn more about the subscriber benefits here.
We discuss:
Why thyroid management is unusually complex and what the thyroid does [2:00];
Why symptoms are insufficient for diagnosis and the risks of underdiagnosis and overtreatment [9:00];
Regulation of the thyroid axis and conversion of T4 to T3 [13:30];
Reverse T3 and the metabolic effects of T3 [20:00];
Thyroid blood tests, assay limitations, and who should be tested [22:45];
Causes and mimics of hypothyroidism and the criteria for diagnosis [29:00];
Navigating subclinical hypothyroidism [34:30];
Treating hypothyroidism with T4 and T3 [37:00];
Hashimoto's disease, pregnancy, and associated autoimmune risks [42:45];
Proper timing and administration of thyroid medication [43:45];
Causes, symptoms, diagnosis, and treatment of hyperthyroidism [45:15];
Iodine excess, the risks of thyroid-support supplements, and evidence for dietary interventions [53:45];
A practical framework for evaluating and treating patients who suspect thyroid dysfunction [59:30]; and
More.
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