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#508: Why Athletes Can Achieve High Performance During an Energy Deficit – Jose Areta, PhD Jan 09, 2024

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About This Episode:

Insufficient energy availability can significantly disrupt normal hormonal, metabolic, and physiological processes, prompting the body to initiate a coordinated response aimed at conserving energy.

While commonly viewed as beneficial for weight loss and managing cardiometabolic conditions in the current obesity epidemic, chronic energy deficiency in the context of modern sports and exercise nutrition is linked to adverse health outcomes and diminished athletic performance.

Nevertheless, the evidence regarding the negative impact of energy deficit on physical capacity and sports performance is not entirely clear.

Although severe energy deficiency can impair physical capacity, it's noteworthy that humans can enhance aerobic fitness and strength even in the presence of significant energy deficits. Strikingly, many elite athletes compete at the highest levels despite displaying evident signs of energy deficiency.

This raises intriguing questions about how the human body adapts to energy deficits, challenging conventional views on the relationship between energy availability and athletic prowess.

To discuss some potential reasons for this ability to maintain peak physical performance while suppressing energetically demanding physiological traits, researcher Dr. Jose Areta of LJMU is on the podcast to discuss his work in this area.

About The Guest:

Dr. José Areta currently works as a lecturer in Sports Nutrition and Metabolism at the School of Sport and Exercise Sciences at LJMU.

José's primary interest is in the area of training-nutrient interactions in humans. In other words, he investigates how to manipulate ingestion of carbohydrates, fat and protein around training to optimise physical performance and health.

The outputs of his research have not only expanded the knowledge of the field but had significant impact and influence on determining current dietary recommendations and practices world-wide.

His work has provided novel insights in relation to the amount, timing, quantity and distribution of carbohydrates, fat and protein and dietary supplements around training. Over the last few years José has been developing his research in the area of the endocrinological, metabolic and physiological effects of energy restriction, in which he is currently growing his research team and capability.

#507: Does a Higher Portfolio Diet Score Reduce Heart Disease? – Andrea Glenn, PhD Jan 02, 2024

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About This Episode:

The Portfolio diet is a nutritional approach that has garnered attention for its ability to reduce blood lipids and thus improve cardiovascular health.

While past intervention trials have demonstrated significant reductions in blood lipids, a critical aspect often overlooked is the long-term impact, both in terms of adherence and disease outcomes.

A recent study aimed to address this by looking at disease risk across three cohorts: the Nurses' Health Study I, Nurses' Health Study II, and the Health Professionals Follow-up Study.

The study made use of a Portfolio Diet Score (PDS), a comprehensive metric that evaluates the diet's efficacy based on specific components.

These components include positive rankings for plant proteins (especially from legumes), nuts and seeds, viscous fiber sources, phytosterols (mg/day), and plant monounsaturated fat sources. Conversely, the PDS negatively ranks foods high in saturated fat and cholesterol.

In this episode, Dr. Andrea Glenn, the lead author of this study, discusses the intricacies of the research, providing insights into its findings and shedding light on how these findings resonate within the broader landscape of literature.

Listener Q&A: Homocysteine, MUFA, Healhty BMI, and more! (Preview) Dec 26, 2023

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This episode is one of our Premium-exclusive AMA (ask me anything) episodes, where we answer questions submitted by Premium subscribers.

To listen to the full 90 minute episode, you'll need to be a Premium subscriber and access the episode on the private Premium feed.

Otherwise, you can hear a preview of the episode here.

Full List of Questions:

[01:50] How should one interpret the systematic reviews done by Hooper et al that report no association between modification or reduction of saturated fat intake with cardiovascular mortality, total mortality, non-fatal MI?
[22.10] Given most people don't meet them, are public health targets for fruit and vegetables too high?
[29.10] What is the role of homocysteine in heart disese? Is it causal?
[40:45] Monounsaturated Fat: Good, Bad or Indifferent?
[50:13] Is there evidence to suggest an upper limit for BMI, where even individuals with a 'healthy' body composition would be at elevated risk?
[59:32] Where does the current research stand on the impact of diet on brain health?
[01:08:48] Based on recent findings, do we have to throw out previous research on diet's impact on the gut microbiome?

#506 Sports Nutrition: Translating Research to Practice – Andreas Kasper, PhD Dec 19, 2023

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About This Episode:

Navigating the intricate landscape of sports nutrition is one that constantly evolves and challenges our understanding of optimal athletic performance.

The delicate balance between advancing research and ensuring practical applicability in the high-speed realm of sports nutrition is a perpetual struggle.

Decision-making is difficult, especially when faced with a scarcity of evidence. It's a challenge that resonates with many professionals in the field, prompting reflections on the art of making informed choices in the absence of conclusive data.

In this episode, Dr. Andy Kasper, PhD shares his experiences and research in the field of elite sports nutrition.

Dr. Kasper, a PhD in Nutrition and Physiology from Liverpool John Moores University, currently spearheads the Performance Nutrition department at Newcastle United Football Club. His illustrious career spans across elite football, rugby union, and rugby league, with notable stints at clubs like Chelsea, Fulham, Derby, England Rugby Union, Sale Sharks, London Irish, and Wasps, to name a few.

A prolific contributor to academic publications, Dr. Kasper's insights have not only shaped the scientific landscape but have also directly influenced the nutritional strategies employed by top-tier athletes.

Our conversation will traverse a myriad of topics, from the transformative changes witnessed in sports nutrition to invaluable advice for practitioners navigating this intricate terrain.

We'll also delve into the delicate balance between advancing research and ensuring practical applicability in the fast-paced world of sports nutrition. Dr. Kasper will shed light on the Paper-to-Podium Matrix, a concept that bridges the gap between scientific discoveries and their real-world implementation in the pursuit of athletic excellence.

#505: Oslo Diet-Heart Study: Cholesterol-lowering Diets & Cardiovascular Events Dec 12, 2023

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About This Episode:

The Oslo Diet-Heart Study was one of the earliest randomized controlled trials to explore the relationship between diet and heart disease. It aimed to investigate the impact of dietary interventions, specifically the reduction of saturated fat intake and an increase in polyunsaturated fat intake, on cardiovascular health.

The Oslo Diet-Heart Study involved 412 men who had already suffered a myocardial infarction 1-2 years before the start of the intervention.

Despite some known limitations, the Oslo Diet-Heart Study played a role in shaping early understanding on the relationship between dietary fat, cholesterol levels, and heart disease. Subsequent research and larger studies have contributed to a more nuanced understanding of the complex factors influencing cardiovascular health.

In this episode we discuss why this trial is important in the history of diet-heart research and how it connects to other seminal work in the field.

#504: Vegetable Oil vs. Saturated Fat – Analysis of the LA Veterans Study Dec 05, 2023

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About This Episode:

In 1959 a landmark clinical trial, often referred to as the LA Veterans Study, began with the aim to investigate the effects of replacing dietary saturated fats with polyunsaturated fats, on the progression of atherosclerosis and cardiovascular outcomes.

This was an eight-year clinical trial in 846 domiciled male veterans in the US. The diets between the control and experimental groups differed by saturated fat and polyunsaturated fat (particularly linoleic acid) content, but were similar in calories and total dietary fat.

The findings of the study suggested that replacing saturated fat with polyunsaturated fat was beneficial for reducing heart disease risk. However, the study also reported an unexpected increase in non-cardiac mortality in the intervention group, which raised concerns.

In this episode, we discuss why the LA Veterans Study was such a seminal trial and what we can learn from it.

#503: Lyon Diet Heart Study – Canola Oil, "Mediterranean" Diets & Minimizing Bias Nov 28, 2023

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The Lyon Diet Heart Study (LDHS) is often cited as one of the pivotal studies that helped establish the Mediterranean diet as a recognized and recommended dietary pattern for cardiovascular health.

A clinical trial conducted in Lyon, France, the LDHS showed significant reduction in cardiac death could be achieved in secondary prevention patients using a dietary intervention.

Conducted between 1992 to 1996, the study involved 605 participants who had previously experienced a heart attack (myocardial infarction).

LDHS showed an incredible 75% lower risk of cardiac death in these patients. This remarkable reduction was unexpected and led to considerable attention from the medical and scientific communities.

LDHS is interesting to dig into for several reasons. First, it's clever methodology was able to account for some challenges of doing nutrition research. Second, the dietary intervention, whilst named as a "Mediterranean diet", should perhaps be considered differently.

In this episode, Alan and Danny dig into all the details, highlighting some important lessons we can take from LDHS.

#502: Sydney Diet-Heart Study – Is Linoleic Acid Causing Heart Disease? Nov 21, 2023

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Past episodes referenced: Episodes 493, 481 & 317
Further reading: How Diet Influences Heart Disease Risk

About This Episode:

The Sydney Diet-Heart Study was a clinical trial conducted in the 1960s and 1970s that aimed to examine the hypothesis that reducing saturated fat intake in the diet would lead to a reduced risk of heart disease.

However, it really only gained attention after a more recent re-analysis by Ramsden et al., which in recent years has been used as supporting evidence for the idea that increased polyunsaturated fat (PUFA), and specifically linoleic acid, in addition to reduced saturated fat intake, can increase heart disease risk.

This was based on the findings that substituting linoleic acid in place of saturated fat increased all-cause, CVD and CHD mortality.

This is of course counter to prevailing consensus and guidelines in this area, which routinely show reduced risk on replacing SFA with PUFA.

Could this trial undermine the common conclusions that replacing saturated fat with polyunsaturated fat decreases heart disease risk?

In this episode Alan and Danny discuss some of the crucial aspects to understand about this study and what it means for what conclusions can be made about the impact of PUFA broadly, and linoleic acid specifically, on our health.

Addressing Some Criticisms of Nutritional Epidemiology (SNP 23) Nov 14, 2023

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Note: This is a Premium-exclusive episode, so in order to listen to the full episode you'll need to subscribe to Sigma Nutrition Premium.

About This Episode

Nutritional epidemiology has faced strong criticism over time. While some of the methodological limitations are fair, often there are criticisms that are misguided and inaccurate.

In this episode, Danny touches on a few examples of the misunderstandings of the field and how such claims can be addressed in a more accurate manner.

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#501: Sex-based Training Recommendations: Evidence-based or Hype? – David Nolan, PhD Nov 07, 2023

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About This Episode:

The field of research exploring sex differences in exercise response has yielded intriguing findings, shedding light on the complex interplay between biology, physiology, and training adaptations.

One of the fundamental areas of investigation pertains to sex disparities in strength, power, and hypertrophy. Historically, it's been well-established that males, on average, exhibit greater absolute strength and muscle mass compared to females. This discrepancy often traces its roots back to inherent physiological distinctions.

However, when it comes to responses to strength and hypertrophy training, the narrative becomes more nuanced. Research indicates that, when individuals of both sexes follow matched resistance training protocols, the relative improvements in strength and hypertrophy are quite similar.

So, do women need to be trained differently than men? The answer, it appears, is not as much as one might assume. The principles of progressive overload, specificity, and other training fundamentals remain constant. While individualization is key, the idea of drastically distinct training guidelines based on sex lacks compelling empirical support.

The guest in this episode, Dr. David Nolan, is a researcher in the area of sex differences in exercise response, and has looked at the influences of menstrual cycle and hormonal contraceptive use in female athletes on their performance.

In this episode, we discuss the research to date, and what this means practically for athletes and coaches.

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