Podcast
Sigma Nutrition Radio
Hosted by Danny Lennon · EN
Discussions about the science of nutrition, dietetics and health. The podcast that educates through nuanced conversations, exploring evidence and cultivating critical thinking. Hosted by Danny Lennon.
638episodes
Episodes
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#558: Rethinking Ultra-Processed Foods in the Modern Food System – Duane Mellor, PhD
Apr 1, 202500:52:08Tap to summarizeDiscussions around ultra-processed foods (UPFs) and their role in public health have gained significant traction in recent years. While some advocate for categorizing and regulating these foods due to their potential negative health effects, others argue that such classifications can oversimplify the issue and detract from more actionable dietary changes. In this episode, Dr. Duane Mellor, a registered dietitian and researcher, joins us to explore the complexities of the UPF debate. Rather than dismissing the concept outright, Dr. Mellor emphasizes the importance of nuanced discussion, bridging the gap between research findings and practical, evidence-based dietary guidance. Throughout this conversation, we unpack the broader implications of ultra-processed foods in the food system, consider how added fat, salt, and sugar contribute to public health challenges, and explore realistic approaches for dietary improvements. Guest Information Dr. Duane Mellor, PhD is a registered dietitian, academic researcher and science communicator. Dr. Mellor is currently working in clinical dietetics, working to support people, families and carers living with diabetes. Previously Dr. Mellor worked in medical education at Aston University, holding the position of Associate Dean for Public Engagement in the College of Health and Life Sciences. After initially working in the areas of clinical trials, Dr. Mellor's other research interests focused on improving nutrition and health by working with communities to celebrate their heritage through food and help tackle barriers resulting from societal inequalities. Timestamps [03:02] Interview start [06:39] Understanding the NOVA classification [09:53] Potential pitfalls and policy implications [14:52] Food science and technology perspectives [20:47] Challenges in food classification [26:13] Health equity and policy considerations [42:31] Communication and public perception [50:30] Final thoughts and advice [51:15] Key ideas segment (Premium-only) Related Resources Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Paper: Mellor, 2024 – The role of food science and technology in navigating the health issues of ultra-processed foods Go to sigmanutrition.com
Transcribe →#557: Health Psychology & Eating Behaviour – Prof. Jane Ogden
Mar 25, 202500:48:46Tap to summarizeIn the realm of health psychology, our understanding of eating behaviors extends beyond mere physiological hunger cues. Research indicates that factors such as learned associations, cultural influences, and individual perceptions play pivotal roles in shaping our dietary choices. Recognizing this complexity is essential for developing effective dietary interventions that move beyond simplistic recommendations, acknowledging the intricate web of cognitive, emotional, and societal factors at play. A significant discussion within nutrition science centers on the regulation of eating patterns, particularly the balance between internal cues and external structures. While intuitive eating emphasizes responding to one's internal hunger signals, studies suggest that these signals are often influenced by external factors such as distractions and learned behaviors. An alternative approach, known as "pinned eating," proposes structuring meals around fixed times and contexts. In this episode Prof. Jane Ogden, Professor of Health Psychology at the University of Surrey, discusses these concepts and some of the research her group has carried out. Guest Information Professor Jane Ogden is a distinguished health psychologist at the University of Surrey, with over three decades of experience in researching eating behavior, weight management, and women's health. She earned her PhD from the Institute of Psychiatry in London in 1990 and has since contributed extensively to the field through her research and publications. Throughout her career, Professor Ogden has authored several influential books, including "Health Psychology: A Textbook," now in its seventh edition, and "Thinking Critically about Research." Her work is widely recognized, leading to her receiving an honorary Doctor of Science from the University of Buckingham in 2022. Timestamps [02:01] Interview start [02:41] Understanding eating behaviors and influences [10:33] Integrating psychology into nutrition practice [13:58] Pinned Eating [16:46] Critique of Intuitive Eating [21:30] Eating behaviors and hunger as a perception [26:34] Taste preferences and acquisition in children [29:10] Cultural and contextual meanings of food [33:25] Disgust and food presentation [35:29] Health communication and obesity [44:28] Future research in health psychology [47:23] Key ideas segment (Premium-only) Links: Subscribe to Sigma Nutrition Premium Join the Sigma email newsletter for free Go to Sigma Nutrition website Enroll in the next cohort of our Applied Nutrition Literacy course Study: Ogden et al., 2020 – The impact of intuitive eating v. pinned eating on behavioural markers: a preliminary investigation
Transcribe →SNP38: What is Quality Sleep?
Mar 18, 202500:22:11Tap to summarizeSleep is one of the most critical yet often overlooked components of health, performance, and overall well-being. Poor sleep quality or insufficient sleep can disrupt circadian rhythms, impair glucose metabolism, and alter hunger signals, leading to increased food intake, reduced insulin sensitivity, and other undesirable outcomes. In this episode, we bring together expert discussions from some of the leading researchers in sleep science, to explore what defines high-quality sleep, the mechanisms behind sleep regulation, and the factors that influence sleep-wake cycles, from light exposure to psychological stress. Timestamps Note: Full episode only available on Sigma Nutrition Premium. [02:14] The importance of sleep duration and timing [05:32] Exploring sleep intensity and architecture [07:50] Defining good quality sleep [12:46] The two process model of sleep regulation [19:06] What is sleep? [24:47] Socioeconomic factors and sleep [34:30] The impact of blue light on sleep [47:10] Wake drive and sleep pressure [52:44] Stress, anxiety, and sleep [58:27] Common sleep disorders [01:06:26] Sleep and eating behavior Related Resources Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Episodes referenced: 38: Dan Pardi, PhD 316: Michael Grandner, PhD 209: Amy Bender, PhD 433: Greg Potter, PhD 328: Meeta Singh, MD 536: Ian Dunican, PhD 61: Kirk Parsley, MD
Transcribe →#556: Can We Restore the Gut Microbiome Through Dietary Changes? – Anissa Armet, PhD
Mar 11, 202501:06:28Tap to summarizeThere is research suggesting that industrialization has significantly altered the composition of our gut microbiota, with certain microbial species now absent in many industrialized populations. Given the known associations between gut microbiome diversity and health, researchers have begun investigating whether restoring lost microbial species and adopting dietary patterns similar to those of non-industrialized populations could lead to measurable health benefits. In a newly-published study, the investigators aimed to explore whether L. reuteri could be successfully reintroduced into the microbiome through the "Restore Diet" and whether such a shift would result in improvements in key cardiometabolic and inflammatory markers. One of the authors, Dr. Anissa Armet, is on the podcast to discuss this area and both the potential and limitations of microbiome restoration efforts. Timestamps [03:48] Interview start [08:45] Understanding gut microbiome restoration [11:44] Challenges in microbiome research [21:03] Study design and objectives [43:23] Key findings and results [47:46] Future research directions [01:04:04] Key ideas segment (premium-only) Links Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Free Book: The NiMe Diet: Scientific Principles and Recipes Paper: Cardiometabolic benefits of a non-industrialized-type diet are linked to gut microbiome modulation Dr. Armet's free, open-access High Protein Cookbook for Muscle Health During Cancer Treatment
Transcribe →#555: What Should the Dietary Guidelines Say? – Prof. Christopher Gardner
Mar 4, 202500:59:29Tap to summarizeEvery five years, the U.S. Dietary Guidelines are updated based on the latest scientific evidence to help shape national nutrition recommendations. A panel of experts was assembled to review the existing research, evaluate new findings, and provide recommendations that will inform the next edition of the guidelines. One of the committee members involved in this process is Professor Christopher Gardner, a leading nutrition scientist at Stanford University, who joins us to share key insights from the committee's work. In this discussion, Professor Gardner provides an inside look into how the committee evaluated dietary patterns, the role of plant-based proteins, and the ongoing debate surrounding ultra-processed foods. He explains the rigorous process of reviewing scientific literature, the challenges in translating research into policy, and the critical role of health equity in shaping the recommendations. By exploring these themes, this episode aims to provide clarity on the scientific foundation behind the upcoming dietary guidelines. Whether you're a nutrition professional, researcher, or someone interested in how dietary recommendations are formed, this conversation sheds light on the key discussions shaping the future of nutrition policy. Timestamps [03:38] Interview begins [07:18] The rigorous process behind formulating dietary guidelines [12:10] Key questions addressed and major findings from the report [25:41] Identifying nutrients of concern and refining dietary patterns [33:39] The importance of health equity in dietary recommendations [36:04] Reassessing dairy's role in different population groups [41:05] Shifting the focus towards plant-based protein sources [47:52] The debate on ultra-processed foods and public health implications [58:24] Key Ideas segment (Premium-only) Related Resources Enroll in the next cohort of our Applied Nutrition Literacy course Subscribe to Sigma Nutrition Premium Join the Sigma email newsletter for free Scientific Report of the 2025 Dietary Guidelines Advisory Committee Previous episode with Prof. Gardner: Episode 223
Transcribe →#554: Crucial Ideas for Understanding Nutrition Science
Feb 25, 202501:13:12Tap to summarizeUnderstanding the complexities of diet-disease relationships requires a nuanced approach to nutritional science. Unlike other scientific disciplines, nutrition research often grapples with the inherent challenges of studying dietary patterns and nutrient intakes in free-living populations over long periods. The cumulative effects of dietary exposures, combined with the necessity to control for confounding factors such as total energy intake and population-specific dietary habits, highlight the need for rigorous study designs and careful interpretation of findings. Despite their utility, these methods are often misunderstood or misrepresented in public discourse. Addressing these misunderstandings requires a clear communication of key principles underpinning nutritional science, including the role of cumulative exposure, the importance of contextualizing absolute and relative risks, and the necessity of evaluating the long-term effects of dietary patterns. This episode aims to provide a comprehensive overview of these essential ideas, equipping readers with the tools to critically appraise the evidence and engage meaningfully with the ongoing conversation around nutrition research. Timestamps [03:26] Understanding nutrition science: core concepts [06:01] Standards of proof in nutrition research [19:39] Unique challenges in nutrition research [26:30] High vs. low exposure in nutrition studies [34:34] Challenges in nutrition randomized control trials [39:29] Understanding null by design in nutrition trials [41:58] The importance of temporal relationships in diet and disease [43:55] Relative risk vs. absolute risk [57:16] The role of substitution and adjustment in nutrition studies Related Resources Enroll in the next cohort of our Applied Nutrition Literacy course Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Episodes referenced: 531: Correlation, Causation & Cliché 478: Exposures in Nutrition – Why They're Crucial to Understand 511: Null By Design – When "No Effect" Doesn't Mean No Effect 378: Nutritional Epidemiology 472: Compared To What? – Understanding Food Substitution Analysis & Adjustment Models
Transcribe →#553: Healthy Habits for Fertility and Reproductive Health – Marjorie Nolan Cohn, RD
Feb 18, 202500:40:58Tap to summarizeThis episode focuses on the intersection of nutrition, lifestyle, and women's health, with a particular emphasis on managing complex conditions such as PCOS, endometriosis, and premenstrual dysphoric disorder (PMDD). Registered dietitian Marjorie Nolan Cohn shares insights from over two decades of clinical practice, highlighting the importance of addressing foundational health behaviors—such as adequate sleep, hydration, and nutrient-dense dietary patterns—before introducing targeted interventions like supplementation. Marjorie explores the nuanced relationship between body weight, metabolic health, and fertility, while addressing misconceptions around weight loss as a primary health goal. The episode examines the role of long-term, individualized care in improving symptoms and outcomes for women experiencing significant menstrual-related challenges. Practical considerations for practitioners, including strategies to build trust, identify key barriers, and provide holistic support, are outlined alongside the importance of interdisciplinary collaboration to improve care quality. Marjorie Nolan Cohn is a registered dietitian with a Masters Degree in Food and Nutrition Science from the Indiana University of Pennsylvania. She is the Clinical Director of Berry Street, a company providing virtual in-network nutritional counseling to people across the US. Timestamps [04:32] Beginning of the interview [08:39] The role of nutrition in fertility [13:40] Understanding PCOS and endometriosis [16:28] Barriers to accurate women's health diagnoses [19:03] Exploring diet and lifestyle strategies [23:28] Addressing challenges in women's health and nutrition [39:01] Closing remarks and final takeaways Related Resources Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Guest website: Berry Street
Transcribe →#552: Diet & Sleep Interactions – Marie-Pierre St. Onge, PhD
Feb 11, 202500:41:04Tap to summarizeOver the past couple of decades, renowned researcher Dr. Marie-Pierre St-Onge has uncovered fascinating links between how we sleep and what we eat, revealing how these two lifestyle factors influence energy balance, cardiovascular health, and metabolic function. In this episode we'll explore Dr. St-Onge's findings on sleep regularity and its association with reduced mortality risk, providing actionable insights for optimizing your lifestyle. With a focus on combining rigorous methodologies and controlled dietary interventions, her research sheds light on the complex mechanisms connecting sleep, diet, and metabolic health. Timestamps: [03:39] Dr. St-onge's academic journey and evolution of her research interests [07:03] Overcoming methodological challenges in sleep and nutrition research [10:20] The importance of sleep regularity for health [15:44] Exploring the bidirectional connection between diet and sleep [23:40] Unpacking the mechanisms linking diet to sleep quality [37:33] Practical recommendations for optimizing sleep and diet Links: Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Article: How Sleep & Nutrition Interact – Alan Flanagan, PhD Go to episode page
Transcribe →Multivitamin Nihilism: Is it Actually Worthless to Supplement? (SNP37)
Feb 4, 202500:17:39Tap to summarizeMultivitamin and multimineral supplements have long been a topic of both scientific inquiry and public debate. While they are often marketed as convenient solutions for achieving nutritional adequacy, their true value remains contentious. Are these supplements essential insurance policies against nutrient deficiencies, or are they merely expensive placebos? Importantly, how should we weigh their potential benefits against the lack of robust evidence for long-term health outcomes such as reduced mortality or chronic disease risk? These questions demand a nuanced exploration, grounded in the context of specific populations and individual needs. Ultimately, the role of multivitamin supplements cannot be assessed in isolation but must be viewed through the lens of context and specificity. How do we balance the biological plausibility of benefits against the variability of individual diets, the presence of fortification policies, and the challenges of achieving dietary adequacy in certain life stages? These considerations invite a more thoughtful and less binary discussion about whether, when, and for whom multivitamins are a worthwhile addition to the diet. Timestamps [00:22] The debate on multivitamins: worthless or beneficial? [00:53] Rationale behind multivitamin use [04:04] Modern nutritional adequacy and multivitamins [07:10] Evidence supporting multivitamin use [23:39] Long-term health outcomes and multivitamins [41:43] Cognitive outcomes [50:18] Pregnancy and multivitamin use Related Resources Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Shaun Ward Article: Multivitamin Madness: There's More to Life than Death Studies mentioned: MacPherson et al., 2013 meta-analysis of randomized controlled trials Jenkins et al., 2021 meta-analysis COSMOS trial – Vyas et al., 2024 analysis of three substudies Loftfield et al., 2024 – Multivitamin Use and Mortality in 3 Cohorts Blumberg et al., 2017 nutritional adequacy paper
Transcribe →#551: How to Shift from Short-term Dieting to Sustainable Lifestyle Changes – Laurin Conlin
Jan 28, 202501:02:19Tap to summarizeWhile the fitness industry often emphasizes short-term goals such as rapid weight loss or aesthetic improvements, a growing body of evidence highlights the importance of fostering long-term habits for health and wellbeing. Understanding how psychological frameworks intersect with physical health behaviors is key to empowering clients and overcoming the challenges posed by rigid dieting practices or the influence of social media culture. Bodybuilding and fitness culture serve as both a microcosm and an extreme example of the challenges faced in this space. As the boundaries between physique sports and general fitness blur, many enthusiasts adopt unsustainable habits without fully understanding their long-term implications. How can fitness professionals effectively guide clients toward intrinsic motivations and healthier relationships with food and exercise while balancing the reality of external pressures? In this episode, Laurin Conlin offers her insights based on her coaching experiences, as well as formal training in exercise sciences and mental health counselling. Dr. Eric Trexler co-hosts the episode with Danny Lennon. Timestamps [05:41] Challenges in dieting and coaching practices [09:58] Bridging physical and mental health through coaching practices [13:15] Recognizing and navigating disordered eating behaviors in fitness clients. [22:01] The physiological and psychological challenges in physique sports. [34:52] Fitness culture and social media influence [37:19] Misunderstanding intuitive eating [41:23] Using motivational interviewing and reflective listening to guide clients [52:13] Integrating mental health practices in fitness and nutrition coaching [62:13] Key Ideas segment (Premium-only) Related Resources Go to episode page Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Sports Nutrition Association Get research reviews from Dr. Eric Trexler and collegues
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