Sigma Nutrition Radio

Effective athlete support requires more than delivering technically correct nutrition advice. It depends on understanding the athlete's wider environment, anticipating the pressures that disrupt good intentions, and building flexible routines that remain useful across training, competition, travel and everyday life.
This episode explores how practitioners can move beyond rigid prescriptions, use "good, better, best" options, measure meaningful progress, and create environments in which athletes can communicate openly about difficulties. It also examines identity, transitions out of sport, and why sustainable support should develop an athlete's autonomy rather than dependence on the practitioner.
To discuss all this is Gemma McGuinness, registered performance nutritionist, former professional footballer and co-founder of Verus Performance.
Timestamps:

[02:38] Interview start
[03:48] Nutrition beyond performance

[10:10] Identity and food choices

[18:47] Standards versus perfectionism

[24:52] Planning that actually works

[28:32] Measuring progress in athletes

[33:37] Where discipline can cause problems

[38:40] Building high performance environments

[45:37] Key ideas (Premium-only)

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Instagram: @gemmcguinnness
Verus Performance
Davey Nutrition
Gemma's Substack

This episode answers one of the questions raised in the most recent Q&A episode on Sigma Nutrition Premium. 
The full episode includes the following questions:
Fiber: Independent effect or proxy for healthy foods?
Exposure frequency for matched dose of red meat
MTHFR gene mutations and 5-MTHF
Typical fish oil supplements vs pharmaceutical-grade products
Health impacts of saturated fat in coconut products
Do I need to consume whole grains?
Could the increasing use of AI pose a threat to doing rigorous science?
To listen to the entire episode (plus the back catalogue of all Premium-exclusive episodes) become a member of Sigma Nutrition Premium.
For episode info and mentioned research go to the episode page here.

Medical screening is often framed as an uncomplicated good: if disease is found earlier, treatment can begin earlier and outcomes should improve.
This episode examines why that reasoning is incomplete. Screening can produce benefit, but it can also generate false positives, incidental findings, overdiagnosis, overtreatment and diagnostic cascades.
Dr. Austin Baraki discusses the distinction between screening people without relevant symptoms and investigating a clinical problem, the probabilistic interpretation of test results, biases that can make screening appear more effective than it is, and the importance of shared decision-making before a test is ordered.
Timestamps:


[03:35] What screening means
[06:36] Choosing what to screen
[11:59] Sensitivity and specificity
[16:54] Predictive value and prevalence
[22:16] Harms of screening and testing
[31:02] Overdiagnosis and biases
[41:40] The $50,000 physical
[44:49] Overdiagnosis vs false positives
[53:03] Overtreatment and surveillance
[57:22] Clinician action bias
[01:02:30] What to screen for
Links:
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Instagram: @austin_barbellmedicine
Twitter: @AustinBaraki

What does the evidence actually show when we look at plant-based dietary patterns through the lens of food processing? And does classifying foods as "ultra-processed" meaningfully change how we interpret the relationship between plant-based diets and long-term health outcomes?
A recent large prospective cohort analysis examined both healthful and unhealthful plant-based dietary patterns, and importantly, stratified the contributing foods based on whether they were classified as ultra-processed or non-ultra-processed.
In this episode, the study's lead author Dr Alysha Thompson, discusses the many intesresting aspects to the analysis. These include how the dietary indices were constructed, the challenges of applying NOVA classification to self-reported dietary data, the role of residual confounding in observational nutrition research, and the extent to which we can or cannot infer independent effects of processing from these findings.
We also consider the broader implications for the use of processing-based classifications in nutrition science and whether this adds meaningful explanatory value beyond traditional assessments of diet quality.
Timestamps


[03:02] Interview start
[05:08] The key research question
[07:52] Study design
[17:25] Building diet scores
[21:11] NOVA classification challenges
[25:04] Key findings
[38:30] NOVA debate and stance
[43:44] Adjustments and mediators
[48:11] Future research directions
[54:37] Key ideas (premium-only)
Resources:

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Paper: Plant-Based Diets, Ultra-Processed Foods, and Risks of Mortality and Major Chronic Diseases: A Prospective Cohort Study

In nutrition and health coaching, one of the central challenges is understanding how people actually change, particularly when life is complex, motivation fluctuates, and behaviour is shaped by emotion, identity, environment, and relationships.
In this episode, Dr. Krista Scott-Dixon discusses the human skills that underpin effective coaching practice. We discuss the importance of the coach–client relationship, the role of therapeutic alliance, and how concepts from counselling and psychology can be used appropriately within scope of practice.
The discussion also explores autonomy-supportive coaching, self-regulation, compassion, acceptance, feedback, and the meta-skills practitioners need in order to improve over time.
Timestamps

[06:10] What makes a competent practitioners?
[11:17] Scope of practice line
[17:49] Therapeutic alliance
[23:33] Applying compassion and acceptance
[31:18] LLMs vs human connection
[34:40] Meta skills for practitioners
[38:51] Getting better feedback
[44:23] Collaboration and autonomy
[55:44] Key ideas recap
Links:
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Enroll in the next cohort of our Applied Nutrition Literacy course
Past episode #326: Adaptability & Autonomy in the Nutrition Coaching Process
Krista's website: kristascottdixon.com
Instagram: @stumptuous
1% Better Academy
The textbook: Applied Nutrition Coaching and Counseling: ebook version
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