Sigma Nutrition Radio

Maintaining the ability to carry out everyday tasks and live independently is often described as a cornerstone of healthy ageing. But what actually happens to muscle strength, power, and functional ability as we get older? And how inevitable is their decline?
At what point do changes in muscle function really begin to matter for day-to-day life? Is loss of strength an unavoidable consequence of ageing itself, or does it reflect something more modifiable? If declines are not fixed, what kinds of training or lifestyle interventions genuinely make a difference, and how strong is the evidence behind them?
In this episode, exercise physiologist Dr Brendan Egan examines these questions through the lens of both epidemiological data and controlled training studies in older adults. What do we learn from short-term resistance training interventions lasting just a few months? Do the gains persist once supervised training ends? And what does this tell us about the practical challenges of maintaining functional capacity over the long term?
The conversation also explores the idea of "use it or lose it" in muscle function, the role of resistance training in extending healthspan, and how exercise programmes can be designed to support independence later in life. Ultimately, the episode asks a simple but crucial question: what does the evidence actually say about staying strong, capable, and functionally independent as we age?
Dr. Brendan Egan is an Associate Professor of Sport and Exercise Physiology the School of Health and Human Performance at Dublin City University. Currently, he is Associate Dean for Research in the Faculty of Science and Health.
Timestamps
[03:49] Understanding functional capacity
[05:56] The importance of muscle strength and mass
[14:09] Epidemiology and strength training
[25:07] Concurrent training in older adults study
[31:05] Barriers to strength training in older adults
[34:18] Misconceptions about older adults and exercise
[39:13] Exercise snacking and SBAE
[51:04] Key ideas segment (Premium-only)
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Nutrient density refers to the concentration of vitamins and minerals in crops relative to their yield. There are widespread claims that today's fruits, vegetables, and grains contain fewer micronutrients than in decades past, often linked to modern farming practices or soil degradation.
This issue is important because if staple crops become less nutritious, it could silently undermine dietary quality and contribute to micronutrient deficiencies ("hidden hunger") in populations.
Dr. Edward Joy is uniquely qualified to address this topic. As a senior research fellow in food systems and nutrition at Rothamsted Research and an associate professor at the London School of Hygiene & Tropical Medicine, his work centers on the intersection of agriculture and nutrition.
In this conversation, Dr. Joy draws on evidence from agronomy and public health to clarify whether the nutrient content of crops has indeed declined, what factors might be responsible (from soil health to plant breeding and climate change), and what we can do to improve the situation.
The discussion emphasizes an evidence-based perspective on soil nutrients, crop varieties, and interventions, cutting through myths to identify real concerns and practical solutions.
Timestamps
[00:55] Interview
[04:49] Understanding nutrient density and soil health
[10:25] Historical evidence and crop experiments
[20:39] Impact of climate change on crop nutrition
[24:05] Potential solutions and future research
[30:34] Translating research to human health
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Rothamsted Research
Dr. Joy's profile page
X/Twitter: @edward_joy1
@NutritionDanny

This is a Premium-exclusive episode of the podcast. To listen to the full episode you need to be subscribed to Sigma Nutrition Premium.
Recently we (Danny Lennon & Alan Flanagan) were invited to 'Processing the Evidence', a "behind closed doors" workshop to discuss the latest scientific evidence on the role of processed foods in human health. The event was organized by Professors Ciarán Forde and Vincenzo Fogliano of Wageningen University in the Netherlands.
The workshop attendees included a range of prominent researchers across a range of domains related to food processing, nutrition science, and public health. The sessions included open discussions on current evidence, knowledge gaps and challenges within the UPF debate.
There were several structured sessions looking at different sub-topics, such as:
Emulsifier-gut interactions
Ultra-processing and its effect on food matrix and bioavailability
Food liking and hedonic overeating
UPFs: Interpreting nutritional epidemiology and RCTs
New trial data: the PROMENADE trial, the RESTRUCTURE Trial, etc.
In this episode, Alan and Danny review some of the key talking points and their takeaways from this event.
Timestamps
[00:31] Event overview: processing the evidence
[04:44] Conference insights with Dr. Alan Flanagan
[07:52] Hypotheses on ultra processed foods
[11:53] Microbiome and additives panel
[21:51] Food science and technology panel
[33:21] Behavioral aspects of food consumption
[38:10] Nutritional epidemiology session
[47:19] Discussion on dietary pattern classification
[50:19] The role of ultra-processed foods in public health policy
[54:18] Clinical and metabolic data on processed foods
[01:00:55] Critique of the NOVA classification system
[01:08:03] Concluding thoughts on ultra-processed foods
[01:23:12] Key ideas and methodological standpoints
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This episode explores how asking better questions and using stronger methods can resolve much of the confusion in nutrition science. Dr. Daniel Ibsen discusses why nutrition research often produces conflicting results and how careful methodological thinking can clarify true diet-disease relationships.
Nutrition science has unique challenges – diets are complex, people self-report their food intake imperfectly, and we can't easily run long-term diet experiments on people. Dr. Ibsen explains how embracing concepts like food substitution analysis, the "target trial" framework, and objective dietary assessment can strengthen evidence.
The episode centers on methodological insights that make nutrition research more reliable and actionable. Key themes include defining dietary comparisons explicitly (the "compared to what?" question), considering people's starting diets, and using causal inference techniques to design better studies.
Daniel B. Ibsen is an epidemiologist and nutritional scientist whose work bridges rigorous causal inference methods with real-world diet and cardiometabolic disease research. He is an Associate Professor at Aarhus University, Denmark.
Timestamps
[00:13] Introduction to the topic
[03:23] Interview start
[08:02] The importance of asking the right questions in nutrition science
[22:18] Understanding causal inference in nutrition
[28:58] Challenges and approaches in nutrition epidemiology
[32:07] Mimicking dietary interventions in studies
[32:55] Target trial framework
[39:52] Objective vs. subjective dietary assessment
[47:01] Why causal effects of ultra-processed foods cannot be identified
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How much do hormonal fluctuations really influence performance and recovery? Should women be adjusting their training and nutrition based on the menstrual cycle? And do female athletes need different protein strategies or recovery protocols than men?
These are questions that have fuelled countless online claims, from rigid "cycle syncing" programmes to supposedly gender-specific nutrition rules. But how much of that is actually grounded in evidence?
In this episode, the conversation tackles those debates head-on, exploring what we truly know about female physiology, adaptation, and recovery, and where confident narratives outpace the science.
You'll hear from four leading experts: Professors Kirsty Elliot-Sale, Stu Phillips, Shona Halson, and Dr. Eric Helms, as they unpack the data on menstrual-cycle variation, autoregulation, and the real determinants of muscle growth and recovery in women.
These discussions were originally recorded live as part of "The Inside Advantage" event hosted by Optimum Nutrition at the McLaren F1 Performance Centre in the UK, where Danny Lennon moderated the session.
Timestamps
[02:07] Introducing the topics of discussion
[07:46] Understanding the menstrual cycle
[09:22] Recovery and hormonal impact
[10:23] Where did "cycle syncing" claims originate?
[15:01] Indirect effects of hormones on performance
[17:28] Sleep and menstrual cycle
[18:46] Training adaptations and hormonal differences
[26:29] Do we have research on female athletes?
[29:20] Muscle building: are there sex differences?
[34:01] Do hormones influence training?
[45:08] Key ideas segment (Premium-only)
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Watch: Optimum Nutrition's 'Inside Advantage' event
Previous episodes with these guests: #'s 452, 280, 192, 454