Fueling Endurance - Nutrition for Runners, Cyclists & Triathletes

It's been one of the most popular supplements of the last few years. A lot of endurance athletes take collagen regularly, but what is it for, how should it be taken, and is there evidence it lives up to the claims? We’re joined by Assistant Prof. Jorn Trommelen, a protein researcher whose lab has done some of the most recent work in this area, to answer our questions. 

Timestamps:

04:00 - Intro and revisiting Jorn's previous episode (Ep. 73)

12:17 - What is collagen (in the body and as a supplement)?

16:53 - The different types of collagen - does it matter?

22:20 - How did collagen become so popular as a supplement?

30:10 - Why are the supplements always hydrolysed collagen or "collagen peptides"?

31:35 - Fueling Endurance Practitioner Membership, T-12 course for athletes, eBook

33:51 - What are the theoretical reasons for taking collagen supplements?

35:28 - Do you actually need collagen or would any source of these amino acids work?

40:56 - Do you need to take Vitamin C along with collagen?

44:53 - State of scientific evidence for collagen - muscle, tendon, bone tissue.

1:01:57 - Jorn's summary and practical recommendations

1:10:11 - Wrap up

 

Guest - Assistant Prof. Jorn Trommelen - Maastricht University

Lab Website: m3-research.nl 

Research Profile: maastrichtuniversity.nl/j-trommelen 

Instagram: @nutritiontactics

 

Studies mentioned in this episode:

Aussieker T et al.  10.1249/MSS.0000000000003596.

Aussieker T et al. The Effects of Ingesting a Single Bolus of Hydrolyzed Collagen versus Free Amino Acids on Muscle Connective Protein Synthesis Rates10.1249/MSS.0000000000003788.

Buchalski A et al. Collagen Supplementation on Tendon-Related Structural and Performance Outcomes: A Systematic Review. J Funct Morphol Kinesiol. 2026. 11(1):130. DOI: 10.3390/jfmk11010130 

 

Fueling Endurance eBook | T -12 Race Nutrition Course | Practitioner Resources

The Fueling Endurance eBook contains answers to 84 of the most common nutrition questions that runners, cyclists and triathletes ask, and contains insights, tips, and quotes from experts and athletes.  The T -12 self-guided course will help prepare you for your next event, with online tools, guides, information and instructions to take you through the 12 weeks leading up to race day. And the Fueling Endurance Practitioner Membership provides access to online tools and calculators I use all the time when working with endurance and ultraendurance athletes. This includes working out the carbohydrate needs for runners (road and trail) and cyclists for different types of training sessions. For more into on each of these, check out fuelingendurance.com.

If you’re planning an ultra-distance running or cycling event, there’s a good chance you’ll be relying on support crew to help get you through it. But what makes a great support crew when it comes to nutrition? How do you best prepare them to support you? And what does success look like? To find out, we're joined by ultrarunner, sport nutritionist, and experienced support crew member, Rachel White.

Timestamps:

04:11 - Rachel's experience as an athlete, crew member, and dietitian

13:20 - The main roles of support crew

21:08 - Preparing support crew before an event

39:46 - Fueling Endurance Practitioner Membership, T-12 course for athletes, eBook

42:02 - Challenges support crew may face during the event (theoretical and practical)

54:48 - Communication between athlete and crew during an event

1:02:09 - What does the optimal crewing experience look like to the athlete?

1:03:52 - Collecting athlete data during an event for post-event analysis

1:10:58 - Final thoughts from Rachel

1:13:26 - Bonus Round

1:19:34 - Wrap up

 

Guest - Rachel White:

Website: rachelwhitenutrition.com

Instagram: @rachelwhitenutrition

LinkedIn: linkedin.com/in/rachel-white-96102896

 

Fueling Endurance eBook | T -12 Race Nutrition Course | Practitioner Resources

The Fueling Endurance eBook contains answers to 84 of the most common nutrition questions that runners, cyclists and triathletes ask, and contains insights, tips, and quotes from experts and athletes.  The T -12 self-guided course will help prepare you for your next event, with online tools, guides, information and instructions to take you through the 12 weeks leading up to race day. And the Fueling Endurance Practitioner Membership provides access to online tools and calculators I use all the time when working with endurance and ultraendurance athletes. This includes working out the carbohydrate needs for runners (road and trail) and cyclists for different types of training sessions. For more into on each of these, check out fuelingendurance.com.

Wearable sweat sensors have entered the market promising easy, accurate, repeatable, and in some cases, real-time feedback on sweat fluid and sodium losses. But do the claims live up to the hype? In this episode, we’ll unpack who these devices might be relevant to, the options currently available on the market, how they work, and most importantly, are they accurate?

Timestamps:

01:01 - Fueling Endurance updates - eBook, Practitioner Membership, Podcast

05:31 - What are wearable sweat sensors?

12:08 - The first step - smart sweat patches

13:39 - Reusable, wearable sweat sensors

20:31 - Nix Biosensor device

22:38 - hDrop

23:09 - Flowbio - newly published validation study

28:47 - My own experiences and comparisons

35:06 - Where does this leave us now?

36:20 - Additional considerations

41:39 - The problem interpreting individual validation studies

43:29 - Wrap up

 

Research mentioned in this episode:

Baker LB. et al. (2020). Skin-interfaced microfluidic system with personalized sweating rate and sweat chloride analytics for sports science applications. Sci Adv. 6:eabe3929. doi: 10.1126/sciadv.abe3929

Bandiera D. et al. (2026). Sweat sodium composition and sweat loss estimation through wearable sensors and predictive equations in dry and humid hot conditions. Front Physiol. 16:1717275. doi: 10.3389/fphys.2025.1717275

 

Fueling Endurance eBook | T -12 Race Nutrition Course | Practitioner Resources

The Fueling Endurance eBook contains answers to 49 of the most common nutrition questions that runners, cyclists and triathletes ask, and contains insights, tips, and quotes from experts and athletes.  The T -12 self-guided course will help prepare you for your next event, with online tools, guides, information and instructions to take you through the 12 weeks leading up to race day. And the Fueling Endurance Practitioner Membership provides access to online tools and calculators I use all the time when working with endurance and ultraendurance athletes. This includes working out the carbohydrate needs for runners (road and trail) and cyclists for different types of training sessions. For more into on each of these, check out fuelingendurance.com.

It's the end of 2025, and like each previous year we’re looking back and providing a brief summary of every question we’ve answered on the podcast in the past year, from “Are high carb diets a health concern for athletes?” to “Do I need a multivitamin?”, and “Can I trust AI with my sports nutrition questions?”. So if you’re new to the podcast and don’t have time to go through the whole back catalogue, or you just want a refresher and the key points from the past year's episodes, this is the place for you.

 

Timestamps:

01:15 - Are high carb diets a health concern for athletes?

03:43 - How does sports nutrition evolve?

05:47 - What is periodised nutrition, and is it beneficial?

10:12 - Can GLP-1 agonists work for runners, cyclists and triathletes?

12:55 - Does nutrition have a role to play in injury prevention?

15:00 - Should I go gluten-free?

17:53 - Can I predict my sweat losses without actually measuring them?

20:13 - Can I trust AI with my sports nutrition questions?

25:03 - Can menthol improve my performance in the heat?

26:57 - Do I need a multivitamin?

30:22 - Is there an optimal drink mix composition?

34:32 - How should I use the new TrainingPeaks carbohydrate and fat calorie metrics?

37:22 - Are omega-3's important for athletic performance?

40:53 - Can my nutrition reduce the chances of getting sick?

44:44 - How much sodium do I need before, during, and after exercise?

48:49 - Can I change my gut microbiome, and will it help me as an athlete?

51:46 - How do I manage exercise, nutrition, and Type 1 Diabetes?

54:05 - 5th anniversary special - Data-driven nutrition planning for ultra-distance events

54:52 - What is exogenous carbohydrate oxidation testing, and how would it benefit me?

59:37 - Wrap up

 

Fueling Endurance eBook | T -12 Race Nutrition Course | Practitioner Resources

The Fueling Endurance eBook contains answers to 49 of the most common nutrition questions that runners, cyclists and triathletes ask, and contains insights, tips, and quotes from experts and athletes.  The T -12 self-guided course will help prepare you for your next event, with online tools, guides, information and instructions to take you through the 12 weeks leading up to race day. And the Fueling Endurance Practitioner Membership provides access to online tools and calculators I use all the time when working with endurance and ultraendurance athletes. This includes working out the carbohydrate needs for runners (road and trail) and cyclists for different types of training sessions. For more into on each of these, check out fuelingendurance.com.

In the past decade, we've gone from low carb to high carb. Are we now heading towards a new era of personalised carb? In this episode I speak to two experts about exactly what exogenous carbohydrate oxidation is, how the testing works, who might benefit from this type of testing, and how to interpret the results.

Timestamps:

04:09 - Tim and Gareth's background and research

10:50 - What is exogenous carbohydrate oxidation?

11:41 - How do you test exogenous carbohydrate oxidation rate?

16:26 - How should an athlete prepare for exogenous oxidation testing?

19:10 - The importance of doing the test properly

22:50 - Are we testing maximal oxidation capacity, or replicating race conditions?

23:44 - What's the real-world benefit of exogenous carbohydrate oxidation testing?

28:17 - Making this testing available to athletes

33:58 - Assumptions, caveats and limitations to exogenous oxidation testing

37:33 - The difference between relative and absolute exercise intensity - does it matter here?

40:52 - What happens when you overfeed carbohydrate during exercise

43:59 - Why Tim and Gareth only test for glucose (and not fructose) oxidation

47:13 - How carb intake recommendations are made based on test results

50:58 - Can you improve exogenous oxidation through exercise or gut training?

57:26 - The (very) high carb trend - will testing help prevent unnecessary carb intake?

1:00:48 - Who might benefit most from testing, and do gut issues predict oxidation abiilty?

1:07:35 - Unanswered questions in this area

1:10:37 - Bonus Round

1:13:42 - Summary, unanswered questions and wrap up

 

Research mentioned in this episode:

Podlogar T, Cooper-Smith N, Gonzalez JT, Wallis GA. (2025). Personalised carbohydrate feeding during exercise based on exogenous glucose oxidation: a proof-of-concept study. Performance Nutrition. 1:2. doi: 10.1186/s44410-025-00003-9

 

Dr Tim Podlogar:

University of Exeter: experts.exeter.ac.uk/43996-tim-podlogar

Instagram: @tpodlogar

LinkedIn: linkedin.com/in/timpodlogar

 

Prof Gareth Wallis:

University of Birmingham: birmingham.ac.uk/staff/profiles/sportex/wallis-gareth

LinkedIn: linkedin.com/in/gareth-wallis-8291a441/

Oxidation testing service (Fuel Sync) coming in Jan 2026

 

Fueling Endurance eBook | T -12 Race Nutrition Course | Practitioner Resources

The Fueling Endurance eBook contains answers to 49 of the most common nutrition questions that runners, cyclists and triathletes ask, and contains insights, tips, and quotes from experts and athletes.  The T -12 self-guided course will help prepare you for your next event, with online tools, guides, information and instructions to take you through the 12 weeks leading up to race day. And the Fueling Endurance Practitioner Membership provides access to online tools and calculators I use all the time when working with endurance and ultraendurance athletes. This includes working out the carbohydrate needs for runners (road and trail) and cyclists for different types of training sessions. For more into on each of these, check out fuelingendurance.com.