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.

• [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)

• Go to episode page
• Join the Sigma newsletter for free
• Subscribe to Sigma Nutrition Premium
• Enroll in the next cohort of our Applied Nutrition Literacy course
• Paper: Plant-Based Diets, Ultra-Processed Foods, and Risks of Mortality and Major Chronic Diseases: A Prospective Cohort Study

Supplement safety is often discussed in very general terms, but in practice the risks depend heavily on the individual. A supplement that is reasonable for one person may be inappropriate for another based on their medications, health conditions, dose, formulation, or the other products they are already using.

This becomes especially important when supplements interact with medications or underlying medical conditions. Some interactions can change how a drug is absorbed, metabolised, transported, or cleared from the body. Others can amplify or oppose the drug's clinical effect, such as increasing sedation, lowering blood pressure or blood glucose, or affecting bleeding risk.

In this episode, Giulia Guerrini, a GPhC-registered pharmacist and researcher at Examine, talks about how clinicians and practitioners can think more systematically about supplement safety, side effects, contraindications, and drug–supplement interactions.

• [02:39] Interview start
• [05:21] Why context matters
• [06:38] Timing and formulation
• [12:58] Rating interaction risk
• [22:39] Berberine benefits and interactions
• [27:33] Adaptogens quality concerns
• [30:15] Melatonin safety questions
• [36:30] Stacking supplements risks
• [41:50] Quality control and regulation
• [55:35] Key ideas segment (premium-only)

Links:

• Free trial of Examine Clinician Edition – For health & nutrition professionals. Includes the Supplement Navigator (safety and interaction checking), plus all other Examine tools (study summaries, supplement database, in-depth guides, etc.)
• Free trial of Examine+ – For anyone wanting to make evidence-based decisions about supplements and health. Includes: 100+ study summaries a month. The full supplement database. In-depth guides. ExamineAI. Doesn't include the Supplement Navigator.
• Go to episode page
• Subscribe to Sigma Nutrition Premium

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.

• [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:

• Go to episode page
• Join the Sigma newsletter for free
• Subscribe to Sigma Nutrition Premium
• 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
  • US
  • Canada
  • UK
  • International