Carbohydrates have always been part of the endurance equation—but how much, when, and which types remain hotly debated. In this listener-driven episode, we tackle those questions and more, exploring a new paradigm in performance fueling that’s reshaping how athletes think about energy during exercise. Dr. Jamie Whitfield, Senior Lecturer at Australian Catholic University’s Mary MacKillop Institute for Health Research, joins us to break it all down.

For years, endurance athletes were trained to conserve carbs by becoming better fat-burners—adapting diet, training, and supplements to spare glycogen. But that thinking is evolving. As Jamie explains, the focus now is on maximizing carbohydrate use. Why? Because carbs are a more oxygen-efficient fuel source than fat—providing more energy per unit of oxygen. That efficiency improvement is a performance advantage in itself—like a supershoe, but internal.

We dig into how elite athletes are pushing 90 to 120 grams of carbs per hour, and what it takes to train the gut to handle it. Are there limits? What happens when intake exceeds demand? Where does the glucose go? Are there health risks? We also explore carb types and ratios, strategies for carrying fuel without excess weight, and how to tailor intake to your individual needs.

Jamie brings clarity to the technical details, helping translate complexity into actionable insight. If you’re fueling training or racing, this episode will reshape your approach to performance nutrition—and maybe your results too.

Show notes and links

Discourse is our VIP community, and it was questions from those listeners that inspired this interview. If you want to be part of the conversation, driving the content, and then engaging with other listeners after the show, you can join by making a small monthly pledge.

• The Podlogar paper that compared 90g/h to 120g/h, informing some of our discussion
• The Jeukendrup study Jamie mentioned that managed to provide 144g/h of carbs with a glucose-fructose mix
• one of the studies mentioned in which glucose ingested spared liver glycogen use during exercise
• A study that looked at performance and tolerance of carb solutions with different ratios of glucose to fructose

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Show notes

In a packed edition of Spotlight, we start our Discourse Digest segment with a dive into the men’s 5000m, where non-African athletes have taken control of the rankings and victories so far in 2025. Is this an aberration, or the beginning of a trend in distance running? We discuss what might be shifting in the sport to close the gap.

Next, we explore the phenomenon of athletes switching national allegiance—this time with Jamaican sprinters now competing for Turkey. Ross and Gareth look at historical examples from track, rugby, cricket and football, while defending the right of athletes to make these switches, and the necessity for sport to minimize them. Discussion shifts to the case of a trans cricketer who has claimed “no advantage” based on test results and comparisons to females. Both the science and logic behind the appeal are bluntly rebutted by Ross, who explains how the science is being misused, and that these "data snapshots" actually reveal a mediocre male with advantage rather than a trans athlete without advantage. We also return to youth sport after Gareth flagged eye-catching performances by 10- and 13-year-olds in the UK. While their talent is undeniable, we ask whether early hype might do more harm than good?

In Ross Replies (30:00), Ross has an 'off-week', because listener Ewan Morris' fascinating insights carry the segment. He explained how some young athletes experience an expiratory flow limitation during breathing, because lung growth outpaces airway development, as yet another challenge that adolescent athletes experience in the journey to adulthood.

In Listener Lens (33:51), we respond to Sean's question about muscle cramps in an ultrarunner he coaches. Ross breaks down two theories—electrolytes vs. fatigue-induced failure of neural regulation—and explains why cramp is far more about the nervous system than sodium and magnesium. We also learn the fascinating reasons why pickle juice may work... but not for the reasons people think, and offer suggestions for what Sean might consider adding to the plan.

In Center Stage (53:33), we revisit sports science's replication crisis. Gareth shares his frustration at the sciences, while Ross explores the structural issues behind shaky science, and offers a partial defence of the failures to produce robust science.

And Finally (1:15:16), we look ahead to Faith Kipyegon’s attempt at a sub-four minute mile, which haunted Ross' dreams, and we make our predictions.

Some links

• Distance running shifts: Aberration or a narrowing gap?
• A review exploring the causes of muscle cramps
• Study showing that electrolyte loss is not associated with muscle cramp
• The pickle juice effect

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In this episode, we’re joined by Dr Joe Warne, founder of the Sports Sciences Replication Center (SSRC) and senior author of a landmark new study that should send shockwaves through the world of sports and exercise science. Joe and his team undertook an enormous replication effort—repeating the methods of previously published research to see if the results hold up. The outcome? Just 28% of the studies could be replicated. Even more striking, the effect sizes dropped by an average of 75% when replicated.

This isn’t just a dent in confidence—it’s a crater. Scientific journals are trusted as sources of truth, yet Joe’s work shows that the majority of findings in this field don’t hold water. Perhaps even more concerningly, only 14% of original study authors were willing to share data or collaborate on replications.

We dig into how the SSRC pulled off this monumental study, why so many findings failed to replicate, and what it reveals about the deep structural issues in the field. From academic incentives to publish fast and flashy, to the natural resistance researchers have to being challenged and falsified, we explore how these forces fuel unreliable and unreproducible science.

Finally, we ask the tough question: what should coaches, athletes, and practitioners do when research can't be trusted? Joe shares his candid thoughts on how science must change—and what needs to happen to restore faith in the evidence base.

This is a must-listen conversation on one of the most pressing issues in science today.

Links

• More of Joe - if you join Discourse by making a small monthly pledge here, you can be like the cool kids and hang out with Joe in our VIP Community!
• Meta analysis in Strength and conditioning
• A webinar Joe Warne did on these issues

The three replication papers:

• The proposal that outlines the selection of papers in more detail
• The 28% paper that outlines the findings
• Reflections from Joe and some of the team on the process and findings

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