Anyone who’s ever done an interval session, or a hard effort in a race, knows that feeling of fatigue setting in as you hold on for dear life. But is this really all the result of lactic acid, or is something else going on? Can the nutrition strategies used in shorter, more intense events like track cycling or rowing now be applied in longer endurance sports to get more out of ourselves during those hard efforts in training or race day? And why, at this years’ Tour de France, are we hearing stories emerge of cyclists consuming lactate, the very thing we’re told is the root cause of all that suffering?

Timestamps:

05:14 - Intro and Bryan's change in workplace

10:42 - Lactate vs lactic acid, and its role in the body

17:08 - Lactate testing, thresholds and what it means for physiology

25:36 - The roles of lactate in body

30:12 - Fueling Endurance Practitioner Membership, T-12 course for athletes, eBook

32:38 - What are buffering supplements and why are they now being used in endurance sports?

40:33 - What is sodium bicarbonate and how does it work?

42:50 - Does the form of sodium bicarb matter (drink vs tablets vs capsules vs mini-tablets/hydrogel)?

49:07 - Sodium bicarb and gastrointestinal issues - how to avoid

54:22 - Dose of sodium bicarb for a performance effect

57:51 - Timing of bicarb for performance - why are cyclists taking it during exercise (rather than before)?

1:03:06 - Is there evidence that bicarb can work for performance in endurance training or competition?

1:05:24 - What is beta-alanine and how does it work?

1:06:50 - Dose and form of beta-alanine and potential side effects

1:09:33 - Need for prolonged supplementation with beta-alanine

1:12:58 - Evidence for beta-alanine or bicarb + beta-alanine combined for endurance performance

1:18:16 - Exogenous lactate supplements/gels

1:20:37 - Is the concept of exogenous lactate supplements new?

1:23:07 - Are the ways exogenous lactate is being used new in professional sport, and is there evidence it works?

1:26:44 - What's likely to happen next with exogenous lactate?

1:28:59 - Bryan's other current research

1:31:45 - Follow up re. exogenous lactate products

1:41:34 - Wrap up

Guest - Dr Bryan Saunders - University of São Paulo

ResearchGate: researchgate.net/profile/Bryan-Saunders-2

X: @Bicycle_Bryan 

Studies mentioned in this episode:

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.

Starchy foods like pasta, rice and potatoes are an important part of the diet for most runners, cyclists, and triathletes. But in an era of pre-packaged meals and reheated leftovers, are we really getting in the carbs we think we are? Starch retrogradation is the process when cooked starchy foods cool down again. Does this reduce the availability of those carbs? And can it be reversed by reheating the food? 

Timestamps:

01:44 - Listener question and background

04:41 - Understanding carbohydrates - sugars and starches

09:00 - Resistant starch

10:04 - What cooking does to starch

14:32 - What happens when starchy foods are cooked then cooled

15:55 - How big is the effect of cooling on digestible carbs?

19:34 - What happens when starchy foods are reheated?

21:07 - Summary

22:03 - 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.

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. 

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.

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.

It’s the fifth anniversary of the podcast! In this special episode, we’re joined by Paul Booth, who put together the nutrition plan for both the men’s and women’s winners of the 2025 Ultra Trail du Mont Blanc, or UTMB. We’ll hear how lots of different topics from previous podcasts came together for these two world class athletes, how lab testing helped inform their nutrition strategies, and how it pays to personalise your strategy based on the athlete’s own data, and not just follow the trends that all the top guys and girls are doing. 

Timestamps:

05:42 - Paul's background and PhD research

11:04 - Paul's role as lead nutritionist for Salomon

18:03 - The evolution in the professionalism of nutrition in ultra trail running

23:46 - Working with the men's and women's winners of UTMB

28:32 - The use lab testing to inform carb intake strategies

38:30 - Understanding the demand for carbs across the event and how the course terrain shapes this

43:30 - Beyond just a grams per hour target - planning carbs and food/fluids for ultra-distance events

54:44 - Gut training for Ruth and Tom

58:09 - Hydration and sodium replacement testing and planning

1:06:32 - Crewing at UTMB

1:09:41 - Reflections on nutrition planning for UTMB and other ultra-distance events

1:11:20 - Applying the lessons from elite athletes to the everyone else

1:16:36 - Bonus Round

1:18:43 - Summary and wrap up

Paul Booth:

Instagram: @ultra.endurance.nutritionist

Website: performancegainsnutrition.com 

If you're interested in participating in Paul's research (in the UK): performancegainsnutrition.com/contact

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.

Juggling training, nutrition, and day-to-day life can be a challenge. But throw in the complexities of Type 1 Diabetes, and it’s a whole new ball game. In this special episode to coincide with World Diabetes Day, I'm joined by co-founder of Enhance-d and former head of research at Team Novo Nordisk, Sam Scott. Sam gives us a peek into the world of diabetes management for the endurance athlete. We’ll discuss what Type 1 diabetes actually is, how it’s managed, the impact of exercise, and the innovations in devices and data management that are making life a little easier to make this all work. Whether you’re an athlete with Type 1, a nutrition practitioner, or you’re just curious what it’s all about, there’ll be plenty in this episode for you.

Timestamps:

03:13 - Sam's background and how he came to work in diabetes and exercise

13:07 - What is Type 1 Diabetes and how is it managed?

25:57 - How does exercise affect blood glucose control with Type 1 Diabetes?

35:26 - Giving insulin with a pen vs a pump for athletes

41:38 - 'Closed loop' systems for glucose monitoring and insulin delivery in athletes

45:41 - Does high volume endurance training make diabetes management harder?

50:11 - Sam's role at Team Novo Nordisk (professional cycling team where all riders have Type 1 Diabetes)

56:59 - Tech and data insights, including Sam's role in founding Enhance-d, and the role of AI in diabetes management

1:08:28 - Very low carb diets and the very high carb (during exercise) trend in athletes with Type 1 Diabetes

1:11:33 - The future of nutrition, exercise and Type 1 Diabetes

1:14:13 - Summary and wrap up

Sam's work:

LinkedIn: linkedin.com/in/sam-scott-phd-620a97a2/ 

Sam's book: Empowered: The Science of Exercise with Type 1 Diabetes (available from Amazon)

Enhance-d (bringing together data on exercise and diabetes management): enhance-d.com 

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.

The gut microbiome is a term that's thrown around a lot. But what does it actually mean? Is there a particular gut microbiome that's more common in athletes? And should athletes be trying to shape their microbiome to benefit their health or performance?

Timestamps:

02:10 - What is the gut microbiome?

13:50 - What are short chain fatty acids, and what's their significance?

18:00 - How do you determine someone's microbiome?

23:59 - Species vs strain of microbiota

30:08 - Is there an "athletic microbiome" that's common to most athletes?

32:00 - Effect of pre/pro/syn/postbiotics on performance

42:38 - Effect of pre/pro/syn/postbiotics on illness prevention and treatment

45:44 - Effect of pre/pro/syn/postbiotics on gut issues during exercise

52:12 - Practical advice for using pre/pro/syn/postbiotics

55:30 - Bonus round and Monash University study

59:14 - Summary and wrap up

Read the research paper (open access):

Gaskell S et al. Gut microbiota and exercise: A systematic review of interventions and evidence limitations. Int J Sports Med. 2025: doi: https://doi.org/10.1055/a-2705-2210 

Current study recruiting at Monash University (looking for distance runners aged 18-55): https://www.monash.edu/medicine/scs/nutrition/research/volunteer#Pre-Exercise 

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.