#380 ‒ The seed oil debate: are they uniquely harmful relative to other dietary fats? | Layne Norton, Ph.D.
Release Date: 01/19/2026
The Peter Attia Drive
In this “Ask Me Anything” (AMA) episode, Peter answers listener questions across a wide range of topics, focusing on how to think through real-world trade-offs and apply scientific evidence in practice. He explores how to build and interpret a meaningful family health history, how individual risk tolerance influences decisions around testing and treatment, and why heart disease remains poorly prevented despite available tools. He also examines whether it’s possible to carry excess body fat while remaining metabolically healthy, outlines the minimum effective dose for strength training...
info_outlineThe Peter Attia Drive
In this episode, Peter explores one of the most foundational topics underlying nearly everything discussed on the podcast: how to think scientifically. Framed as an introspective deep dive, he examines why scientific thinking is inherently difficult for humans, the cognitive biases and tendencies that make it challenging to separate belief from evidence, and why these challenges are even more consequential in today’s environment saturated with misinformation. He also offers a framework for improving our ability to evaluate claims, question assumptions, and identify a personal panel of...
info_outlineThe Peter Attia Drive
In this episode, Peter takes a deep dive into prostate cancer screening, explaining why advanced and metastatic diagnoses continue to rise despite the availability of screening tools, and what can be done to reverse this trend. He breaks down what PSA actually measures and why it is far more informative when tracked over time rather than interpreted as a single value, and he explores how tools like MRI, PSA density, PSA velocity, and improved biopsy techniques can both reduce unnecessary procedures and improve the detection of aggressive cancers. Peter also discusses the role of active...
info_outlineThe Peter Attia Drive
In this “Ask Me Anything” (AMA) episode, Peter explores the topic of gray-market peptides, one of the most requested and most confusing topics he’s covered on The Drive. Peptides sit at the intersection of biological plausibility, clinical promise, and aggressive commercialization, and are often marketed as cutting-edge therapies for everything from muscle repair and longevity to cosmetic enhancement. Rather than promoting or dismissing peptides wholesale, Peter lays out a clear, repeatable framework for evaluating any peptide or drug—covering mechanism, intended effects, safety,...
info_outlineThe Peter Attia Drive
In this episode, Peter takes a deep dive into the science and application of aging clocks, unpacking what they are, the differences between chronological age, biological age, and the pace of aging, and what epigenetic clocks may actually be measuring. He explores key research in the field, including a randomized controlled trial that tested simple lifestyle interventions against several commonly used aging clocks, as well as a study using brain MRI to assess the pace of aging and its relationship to dementia risk and mortality. Throughout the episode, Peter highlights the promises and...
info_outlineThe Peter Attia Drive
In this “Ask Me Anything” (AMA) episode, Peter answers listener questions across a wide range of topics, focusing on practical decision-making and real-world application. He explores how health priorities and strategies should evolve across different decades of life, which chronic diseases are most challenging to manage and how to think about risk hierarchies, and which emerging interventions—beyond exercise—show the most promise for dementia prevention. Peter also breaks down the utility of wearables and explains how to use and interpret DEXA scans effectively. He discusses the...
info_outlineThe Peter Attia Drive
In this special episode, Peter takes a deep dive into obicetrapib, an investigational drug that has captured his attention and renewed interest in an entire class of therapies known as CETP inhibitors. He explains what obicetrapib is and how it works, revisits the history of CETP inhibitors and why earlier versions of these drugs failed—sometimes dramatically—and breaks down the key clinical trials designed to evaluate their impact on cardiovascular risk. Peter examines how obicetrapib influences major lipid biomarkers, including LDL cholesterol and lipoprotein(a) [Lp(a)], and discusses...
info_outlineThe Peter Attia Drive
Layne Norton is a nutrition scientist and accomplished power athlete,who returns to The Drive for a conversation that departs from the show’s usual format. In this episode, Layne presents the evidence-based case that seed oils are not uniquely harmful under isocaloric conditions, while Peter steelmans the strongest versions of the opposing argument that seed oils are inherently harmful. They examine how scientific bias and evidence are evaluated, revisit the historical randomized controlled trials that shaped the seed oil controversy, and explore the mechanistic biology underlying LDL...
info_outlineThe Peter Attia Drive
In this “Ask Me Anything” (AMA) episode, Peter brings together his most up-to-date thinking on cardiorespiratory fitness into a single, practical guide designed to help listeners structure training for maximal impact on healthspan, lifespan, and long-term independence. He explains why cardiorespiratory fitness is one of the strongest modifiable predictors of longevity, clarifies what zone 2 training actually represents and how it differs from higher-intensity work, and addresses persistent confusion around exercise volume, intensity, and time constraints. The discussion covers how to...
info_outlineThe Peter Attia Drive
Abbie Smith-Ryan is a leading researcher in exercise physiology whose work focuses on how training and nutrition influence body composition, metabolism, cardiovascular health, and women’s health across the lifespan, with particular attention on perimenopause and post-menopause. In this episode, Abbie explains how early exercise and play help build the foundation for bone health, muscle development, and cardiorespiratory fitness in girls, as well as how puberty and menstruation shape athletic performance, motivation, and recovery. She also explores how women can tailor training and...
info_outlineView the Show Notes Page for This Episode
Become a Member to Receive Exclusive Content
Sign Up to Receive Peter’s Weekly Newsletter
Layne Norton is a nutrition scientist and accomplished power athlete,who returns to The Drive for a conversation that departs from the show’s usual format. In this episode, Layne presents the evidence-based case that seed oils are not uniquely harmful under isocaloric conditions, while Peter steelmans the strongest versions of the opposing argument that seed oils are inherently harmful. They examine how scientific bias and evidence are evaluated, revisit the historical randomized controlled trials that shaped the seed oil controversy, and explore the mechanistic biology underlying LDL oxidation and atherosclerosis. Along the way, Layne unpacks the chemistry and processing of modern seed oils, assesses evolutionary and ancestral nutrition arguments, clarifies the relationship between seed oils, ultra-processed foods, and contemporary dietary patterns, and situates these questions within the larger context of lifestyle factors that drive cardiometabolic health. Layne concludes by offering practical considerations around dietary fats, cooking oils, and real-world food choices.
We discuss:
- The idea behind this episode, biases, and evidence-based thinking [5:15];
- The four core arguments behind claims that seed oils are harmful [12:30];
- The Minnesota Coronary Experiment (MCE) [14:30];
- The differences among saturated, monounsaturated, polyunsaturated, and trans fats, and why those differences matter for cardiovascular disease [18:30];
- Missing trans fat data as a confounder in the Minnesota Coronary Experiment, other limitations of that study, and the challenge detecting meaningful differences in hard outcomes through nutrition research [24:00];
- The Sydney Diet Heart Study (SDHS): an attempt to address the “duration problem” by enrolling a much higher-risk population [28:30];
- Debating whether evidence from randomized trials supports the idea that seed oils are uniquely harmful once major confounders are removed [34:00];
- The Rose Corn Oil trial: an often-cited study used to argue against polyunsaturated fats [36:30];
- Three studies where replacing saturated fat with polyunsaturated fat produced different results than earlier trials [41:30];
- Layne’s explanation for why the evidence is pointing towards cardiovascular risk reduction when substituting polyunsaturated fat for saturated fat [47:30];
- What Mendelian randomization says about the causal role of LDL cholesterol in ASCVD [56:45];
- The compounding effects of life-long exposure to high LDL cholesterol [1:06:45];
- Does the linoleic acid (omega-6) content of seed oils cause inflammation? [1:13:45];
- Does the linoleic acid (omega-6) content of seed oils increase oxidized LDL? [1:19:30];
- Layne’s analogy to explain why lower LDL particle number outweighs higher per-particle oxidation risk when comparing polyunsaturated fats to saturated fats [1:26:15];
- The role of oxidized LDL in CVD: exploring differences in a diet high in polyunsaturated fat (seed oils) versus high in saturated fat [1:28:00];
- Examining whether industrial processing and solvent extraction of seed oils—especially residual hexane—could plausibly cause long-term harm [1:34:00];
- The evolutionary and “ancestral diet” argument against seed oils [1:40:45];
- Weighing concerns about industrial processing of seed oils against the totality of metabolic and cardiovascular evidence [1:47:30];
- Practical considerations around dietary fats, cooking oils, and real-world food choices [1:50:00];
- Comparing the health impact of seed oils with that of caloric intake and activity levels, and how to prioritize interventions [2:00:15];
- More.
Connect With Peter on Twitter, Instagram, Facebook and YouTube