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This episode examines dietary fiber through the lens of a practical, clinically relevant question: if higher fiber intakes are consistently associated with reduced chronic disease risk, what intake level should we be aiming for to meaningfully improve health outcomes?

The discussion deliberately spans from common online claims that fiber is "not essential" (and therefore unnecessary), through to mechanistic reasoning and the highest-quality evidence we have for hard outcomes and accepted intermediate cardiometabolic endpoints.

Across the episode, we'll hear from six expert perspectives to integrate epidemiology, controlled feeding studies, and clinical guideline contexts.

We will consider how the dose–response patterns, fiber type/source, individual tolerance, and the limitations of nutrition trials all influence what can be recommended with confidence.

• [03:51] Addressing the claim "fiber is not an essential nutrient"
• [11:23] Carbohydrate quality and fiber
• [17:16] Dietary recommendations for fiber
• [20:01] Portfolio diet and cardiovascular health
• [26:48] Comparing fiber sources
• [36:07] Epidemiological evidence on fiber
• [41:57] Understanding fiber intake and coronary heart disease
• [43:23] Fiber intake and colorectal cancer
• [54:06] Diet swap study: south african vs. african american diets
• [01:01:47] High fiber diets and diabetes
• [01:16:18] Challenges in fiber intake and IBS
• [01:21:45] Concluding thoughts on fiber intake

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Dr. José Areta and colleagues recently carried out a human intervention study examining how a pronounced, short-term energy deficit interacts with an aerobic training stimulus to shape endocrine, metabolic, and skeletal muscle proteomic adaptations.

The core premise is that "low energy availability" is often discussed in a largely unidirectional risk framework, yet human physiology evolved under intermittent energy scarcity, and therefore adaptive responses may be more nuanced than "energy deficit equals impaired adaptation."

The study used tightly controlled diet and exercise, repeated muscle biopsies, and dynamic proteomic profiling to quantify both abundance and synthesis rates of hundreds of individual muscle proteins. This enables a more granular view of "muscle quality" and phenotype than traditional bulk muscle protein synthesis measures.

The findings were incredibly interesting and could have implications for how we view the impact of energy deficits and exercise response.

We discuss the implications for athletes who routinely encounter transient within-day or multi-day energy deficits, for weight loss contexts, and for broader questions around healthspan and ageing biology.

• [02:27] Guest introduction
• [03:28] Research background and study design
• [12:18] Study findings: weight loss and endocrine responses
• [15:47] Muscle adaptations and proteomic analysis
• [21:47] Interpreting the results: evolutionary and practical implications
• [26:57] Mitochondrial proteins and muscle adaptation
• [28:44] Energy deficit as a stressor
• [34:26] Case study: female tour de france athlete
• [40:20] Implications for clinical populations
• [41:44] Future research directions
• [46:48] Key ideas segment (Premium subcribers only)

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• X: @jlareta

While the term "hyperpalatable" has been used frequently for considerable time to refer to foods that are so appealing and tasty that they drive overeating, this term hasn't been well-defined nor has there been a universal standard for what it means.

One researcher who set out to create an objective definition for hyper-palatable foods (HPFs) is Dr. Tera Fazzino. Using specific defined thresholds of sugar, fat and salt combinations, Dr. Fazzino and colleagues have looked at the impact of consumption of these HPFs.

In this episode, we delve into defining HPFs and their nutrient profiles, whether they have addictive-like properties, how HPFs differ from (and overlap with) ultra-processed foods (UPFs), the mechanisms by which these foods drive overconsumption, and the broader public health implications.

Tera Fazzino, PhD, is an associate professor of psychology at the University of Kansas. Her research focuses on addiction, obesity, and eating-related behaviors.

• [03:39] Interview begins
• [05:05] Attempting to define hyper palatability
• [10:03] Nutrient combinations in hyper palatable foods
• [14:54] Prevalence of hyper palatable foods
• [17:43] Debate on ultra processed foods
• [30:02] Mechanisms behind hyper palatability
• [35:06] Addiction theory and hyper-palatable foods
• [43:38] Early exposure and long-term effects
• [50:53] Key ideas recap

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