In this episode, Danny answers questions submitted by Premium subscribers.

1. [00:05:13] Is eating too early (relative to chronotype) metabolically problematic?
2. [00:16:55] Can plant-based diets reverse cardiovascular disease?
3. [00:32:54] Are multivitamins useful insurance, or a waste with a good diet?
4. [00:44:56] Does coevolution with foods determine human compatibility and benefit?
5. [00:56:25] How should consumers choose supplement formulations and brands?
6. [01:04:46] Folate vs folic acid: differences and best choice for women of childbearing age?
7. [01:12:37] How reliable is omega-3 content in farmed salmon, especially imported frozen salmon?
8. [01:19:18] How accurate are food labels for metabolizable energy and absorption, especially across processing levels?
9. [01:23:58] Protein needs in breastfeeding and general rehabilitation (non-sport injury)?

To listen to the full episode, subscribe to Sigma Nutrition Premium.

• Go to episode page (with full resource list)
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• Resources for this episode:
  • Eckel et al., 2015 – Morning Circadian Misalignment during Short Sleep Duration Impacts Insulin Sensitivity
  • Stothard et al., 2020 – Early Morning Food Intake as a Risk Factor for Metabolic Dysregulation
  • Ep. #470: Melatonin, Meal Timing & Glucose Tolerance
  • Ep. #579: Is Your Chronotype Hard-Wired or Modifiable?
  • Article: A Plant Based Diet Reverses Heart Disease: True or False?

"The more we learn about the world, and the deeper our learning, the more conscious, specific, and articulate will be our knowledge of what we do not know, our knowledge of our ignorance. For this, indeed, is the main source of our ignorance — the fact that our knowledge can be only finite, while our ignorance must necessarily be infinite." – Karl Popper

To mark Sigma Nutrition's milestone 600th episode (and 12-year anniversary), Danny and Alan examine several areas in which their views have changed, softened, strengthened, or remained stable over the lifespan of the podcast.

The discussion is therefore not only about nutrition itself, but also about the process of scientific reasoning: how positions are formed, what type of evidence can shift them, and why changing one's mind is often a sign of better thinking rather than inconsistency.

The episode therefore serves as both a review of several specific nutrition controversies and a lesson in scientific epistemology. They discuss topics such as red meat, protein, dietary cholesterol, omega-3s, flavonoids, and sodium.

• [11:04] Time-restricted eating
• [19:32] Protein intake, quality & dosing
• [35:04] Cocoa flavanols and cognition
• [51:38] Unprocessed red meat
• [01:05:23] Omega-3 supplementation
• [01:23:10] Dietary cholesterol
• [01:44:41] Sodium J-curve myth
• [01:53:41] Energy balance model

Links

• Go to episode page (with study links & resources)
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• Enroll in the next cohort of our Applied Nutrition Literacy course

This episode examines whether unprocessed red meat has a causal role in (1) type 2 diabetes risk and intermediate measures of glucose intolerance (insulin resistance, beta cell dysfunction, glycemic markers) and (2) cardiovascular disease (CVD) risk.

While there is commonly observed risk signal from observational cohorts, there exist short-term randomized controlled trials (RCTs) that show largely null effects on glucose homeostasis. This had led to differing opinions and interpretations of the evidence base.

Some feel that in the context of an otherwise healthy diet, there isn't much to suggest concern about consuming unprocessed red meat. While others are of the view that there does exist a risk and that limiting or even avoiding consumption is prudent.

The crucial concept of replacement effects is discussed. Increasing red meat intake always means decreasing something else or increasing total energy intake. Therefore, interpreting evidence requires specifying the comparator food(s), the background dietary pattern, the dose, the cut (lean vs fatty), and how the meat is prepared.

To discuss their interpretations of this contentious evidence base, Dr. Mario Kratz and Dr. Gil Carvalho join the podcast to go through the studies most directly related to these questions.

• [06:20] Red meat's impact is debated
• [10:54] Mechanisms linking meat to diabetes
• [15:31] Cohort evidence on diabetes risk
• [24:43] Differences between cohorts and threshold effects
• [33:13] RCT evidence and substitution trials
• [45:49] Why comparator foods matter
• [50:43] RCT examples and mixed results
• [01:00:30] Is there cardiovascular risk beyond saturated fat?
• [01:08:10] Epidemiology patterns and dose thresholds
• [01:11:36] Personal recommendations and risk tolerance
• [01:16:19] Key ideas

• Go to episode page (study links, guest bios, additional resources)
• Join the Sigma email newsletter for free
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• Enroll in the next cohort of our Applied Nutrition Literacy course
• Mario's YouTube channel: Nourished By Science
• Gil's YouTube channel: Nutrition Made Simple!