Triathlon Nutrition Academy

Off-season nutrition is where your next triathlon season gets won or lost, so which of these 3 mistakes are you making right now?
After two decades of working with triathletes, I can tell you that the athletes who struggle most in race season usually got it wrong months earlier, in the off-season. I walk you through the 3 off-season nutrition mistakes I see over and over, why they happen and what they cost you in your next build, plus the athlete who put on at least 10kg every off-season and the former MMA fighter who lost 8kg without losing muscle or bike power. If you’re in the Northern Hemisphere, your off-season starts now. If you’re racing through an Australian summer, bank this one for when your season wraps up.
WHAT YOU’LL LEARN
Why a 2-week break after your A race turns into a 3-month blowout, and what it costs you in your next build
How the blowout and the crash diet feed each other, and why elite athletes don’t get stuck in that cycle
Why the hours you spend in an energy deficit during the day matter as much as your daily total
What dieting hard in the off-season does to the muscle you’re trying to build in the gym
Why doing nothing feels like the safe option, and why it carries last season’s problems straight into the next one
How long a new habit takes to stick, and why that makes the off-season the time to start
TIMESTAMPS
00:59 Mistake 1: The 10kg off-season blowout
03:52 The athlete who gained 10kg every off-season
06:36 Mistake 2: Dieting too hard in the off-season
09:13 How Dan lost 8kg without losing power
11:16 Why a hard diet blunts muscle gains
12:53 Mistake 3: Doing nothing in the off-season
14:30 Why your nutrition needs periodising too
16:49 How long a new habit takes to stick
STUDIES MENTIONED
Lally, P., van Jaarsveld, C. H. M., Potts, H. W. W., & Wardle, J. (2010). How are habits formed: Modelling habit formation in the real world. European Journal of Social Psychology, 40(6), 998–1009. https://doi.org/10.1002/ejsp.674
Murphy, C., & Koehler, K. (2022). Energy deficiency impairs resistance training gains in lean mass but not strength: A meta-analysis and meta-regression. Scandinavian Journal of Medicine & Science in Sports, 32(1), 125–137. https://doi.org/10.1111/sms.14075
Torstveit, M. K., Fahrenholtz, I., Stenqvist, T. B., Sylta, Ø., & Melin, A. (2018). Within-day energy deficiency and metabolic perturbation in male endurance athletes. International Journal of Sport Nutrition and Exercise Metabolism, 28(4), 419–427. https://doi.org/10.1123/ijsnem.2017-0337

RESOURCES MENTIONED
Ep 98: How to Find Balance Post-Race So You Don’t Blow Out and Gain 10kg / 20lb
Ep 255: Over 45 and Losing Power? Your Protein Isn’t Working Like It Used To
FIND THE MISTAKES HIDING IN YOUR RACE DAY NUTRITION
If you heard yourself in even one of these off-season mistakes, I bet there are a few more hiding in your race day nutrition too. My free 5-part audio series walks you through the biggest nutrition mistakes costing you time on race day. It’s short, it’s free and it fits into your next wind trainer session. Grab the free audio series

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The Triathlon Nutrition Academy® is a podcast by Dietitian Approved®. All rights reserved.
See omnystudio.com/listener for privacy information.

Race-day gut issues followed Marie Stevenson through 8 years of triathlon, and she’s a family doctor. So how did she race the IRONMAN 70.3 World Championship in Nice without them?
Marie is a family doctor from Calgary, Canada, who has been racing triathlon for 17 years. She thought her nutrition was great, yet for 8 of those years she planned every run around where the portaloos were. She shares what she used to eat on race day, the everyday fuelling gap she had no idea she was carrying and the 3 changes she credits for her first race without gut issues in 8 years. She also explains how she rebuilt her carb load in a foreign country when the bag holding her race food was stuck in Amsterdam during race week.
WHAT YOU’LL LEARN
What Marie ate on race day for years, and why it kept letting her down
What 8 years of trial and error did and didn’t fix
The daily fuelling gap hiding behind a diet she believed was great
How she rebuilt her carb load when her race bag went missing before 70.3 Worlds
The 3 changes she credits for racing Nice with no gut issues
Why it’s never too late for a masters athlete to change how they fuel
TIMESTAMPS:
01:22 From marathon runner to reluctant triathlete
06:14 Her race nutrition before TNA
07:30 8 years of race-day gut issues
10:54 Why a doctor finally fixed her fuelling
12:31 The daily fuelling gap she missed
16:03 Carb loading properly for the first time
18:25 Fuelling a 1,500km cycling trip
20:57 Race week chaos at 70.3 Worlds
29:51 What fixed her gut in Nice
32:34 Better sleep and changes for her patients
34:59 Advice for masters triathletes
ABOUT MARIE
Dr Marie Stevenson is a family doctor from Calgary, Canada, and a Triathlon Nutrition Academy athlete. She took up running at 47, has run 30 marathons and qualified for the Boston Marathon along the way. She has been racing triathlon for 17 years and finished 12th in the 65 to 69 age group at the 2026 IRONMAN 70.3 World Championship in Nice, France.
RESOURCES MENTIONED
Ep 259: How 5 Masters Triathletes Fuelled the Hilliest 70.3 in the World
FUELLING THAT HOLDS UP WHEN RACE WEEK FALLS APART
Marie’s fuelling held up in Nice because she understood why her plan worked, which meant she could rebuild it on the fly. That’s what I teach inside the Triathlon Nutrition Academy, my education program where you learn how to fuel properly for training, racing and the rest of your life. Register your interest for the next cohort
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The Triathlon Nutrition Academy® is a podcast by Dietitian Approved®. All rights reserved.
See omnystudio.com/listener for privacy information.

Two of the best triathletes on the planet came undone in the Kona heat in back-to-back years, so how do you fuel a hot race without falling apart on the run?
After two decades of working with triathletes, I can tell you that most hot races are won or lost before the gun even goes off. As an age-grouper you’re out on course for hours longer than the pros, in the hottest part of the day, often on a race nutrition plan you built and tested through winter. I break down what the heat actually does to your body, why falling apart in a hot race comes down to much more than toughness and what should change in your plan when the forecast says it’s going to be a scorcher.
WHAT YOU’LL LEARN
Why your body burns through stored carbohydrate faster in the heat, and why your aid stations can only top up so much
The 3 ways triathletes fall apart in a hot race that look identical from the side of the road, and why they need opposite fixes
Why “it’s hot, drink more” is the advice that puts age-groupers in the medical tent
What heat does to your gut, and why backing off your fuel can make it worse
The 4 mistakes I see over and over when the forecast is hot
How one of my Academy athletes went from walking between poles at Spudman to crossing the line at the 70.3 World Championship in Nice
TIMESTAMPS
00:00 Introduction
01:28 How heat changes your body's job
03:30 3 ways to fall apart in a hot race
07:03 Why your gut struggles in the heat
09:16 4 mistakes when the forecast is hot
13:08 How to prepare for a hot race
STUDIES MENTIONED
Almond, C. S. D., Shin, A. Y., Fortescue, E. B., Mannix, R. C., Wypij, D., Binstadt, B. A., Duncan, C. N., Olson, D. P., Salerno, A. E., Newburger, J. W., & Greenes, D. S. (2005). Hyponatremia among runners in the Boston Marathon. New England Journal of Medicine, 352(15), 1550–1556. https://doi.org/10.1056/NEJMoa043901
González-Alonso, J., Teller, C., Andersen, S. L., Jensen, F. B., Hyldig, T., & Nielsen, B. (1999). Influence of body temperature on the development of fatigue during prolonged exercise in the heat. Journal of Applied Physiology, 86(3), 1032–1039. https://doi.org/10.1152/jappl.1999.86.3.1032
Hew-Butler, T., Rosner, M. H., Fowkes-Godek, S., Dugas, J. P., Hoffman, M. D., Lewis, D. P., Maughan, R. J., Miller, K. C., Montain, S. J., Rehrer, N. J., Roberts, W. O., Rogers, I. R., Siegel, A. J., Stuempfle, K. J., Winger, J. M., & Verbalis, J. G. (2015). Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clinical Journal of Sport Medicine, 25(4), 303–320. https://doi.org/10.1097/JSM.0000000000000221
Jentjens, R. L. P. G., Wagenmakers, A. J. M., & Jeukendrup, A. E. (2002). Heat stress increases muscle glycogen use but reduces the oxidation of ingested carbohydrates during exercise. Journal of Applied Physiology, 92(4), 1562–1572. https://doi.org/10.1152/japplphysiol.00482.2001
McCubbin, A. J., Allanson, B. A., Caldwell Odgers, J. N., Cort, M. M., Costa, R. J. S., Cox, G. R., Crawshay, S. T., Desbrow, B., Freney, E. G., Gaskell, S. K., Hughes, D., Irwin, C., Jay, O., Lalor, B. J., Ross, M. L. R., Shaw, G., Périard, J. D., & Burke, L. M. (2020). Sports Dietitians Australia position statement: Nutrition for exercise in hot environments. International Journal of Sport Nutrition and Exercise Metabolism, 30(1), 83–98. https://doi.org/10.1123/ijsnem.2019-0300
Mougin, L., Macrae, H. Z., Taylor, L., James, L. J., & Mears, S. A. (2025). The effect of heat stress and dehydration on carbohydrate use during endurance exercise: A systematic review and meta-analysis. Sports Medicine, 55(11), 2825–2847. https://doi.org/10.1007/s40279-025-02294-3
Parkin, J. M., Carey, M. F., Zhao, S., & Febbraio, M. A. (1999). Effect of ambient temperature on human skeletal muscle metabolism during fatiguing submaximal exercise. Journal of Applied Physiology, 86(3), 902–908. https://doi.org/10.1152/jappl.1999.86.3.902
Périard, J. D., Racinais, S., & Sawka, M. N. (2015). Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports. Scandinavian Journal of Medicine & Science in Sports, 25(S1), 20–38. https://doi.org/10.1111/sms.12408
Roberts, W. O., Armstrong, L. E., Sawka, M. N., Yeargin, S. W., Heled, Y., & O’Connor, F. G. (2021). ACSM expert consensus statement on exertional heat illness: Recognition, management, and return to activity. Current Sports Medicine Reports, 20(9), 470–484. https://doi.org/10.1249/JSR.0000000000000878
Snipe, R. M. J., Khoo, A., Kitic, C. M., Gibson, P. R., & Costa, R. J. S. (2017). Carbohydrate and protein intake during exertional-heat stress ameliorates intestinal epithelial injury and small intestine permeability. Applied Physiology, Nutrition, and Metabolism, 42(12), 1283–1292. https://doi.org/10.1139/apnm-2017-0361
Snipe, R. M. J., Khoo, A., Kitic, C. M., Gibson, P. R., & Costa, R. J. S. (2018). The impact of exertional-heat stress on gastrointestinal integrity, gastrointestinal symptoms, systemic endotoxin and cytokine profile. European Journal of Applied Physiology, 118(2), 389–400. https://doi.org/10.1007/s00421-017-3781-z
Speedy, D. B., Noakes, T. D., Rogers, I. R., Thompson, J. M. D., Campbell, R. G. D., Kuttner, J. A., Boswell, D. R., Wright, S., & Hamlin, M. (1999). Hyponatremia in ultradistance triathletes. Medicine & Science in Sports & Exercise, 31(6), 809–815. https://doi.org/10.1097/00005768-199906000-00008
van Wijck, K., Lenaerts, K., Grootjans, J., Wijnands, K. A., Poeze, M., van Loon, L. J. C., Dejong, C. H. C., & Buurman, W. A. (2012). Physiology and pathophysiology of splanchnic hypoperfusion and intestinal injury during exercise: Strategies for evaluation and prevention. American Journal of Physiology: Gastrointestinal and Liver Physiology, 303(2), G155–G168. https://doi.org/10.1152/ajpgi.00066.2012
RESOURCES MENTIONED
Ep 214: Sweat Science
Ep 251: How Do You Carb Load for a Triathlon Without Feeling Bloated and Heavy?
Ep 253: Is Carb Loading a Myth?
START YOUR HOT RACE WITH A FULL FUEL TANK
If you have a hot race coming up in the next 12 months, the fuel tank you take to the start line is your buffer. My Carb Loading Masterclass shows you exactly how much carbohydrate to eat, when to eat it and what to eat, so you can carb load properly without feeling heavy and bloated. Get the Carb Loading Masterclass
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The Triathlon Nutrition Academy® is a podcast by Dietitian Approved®. All rights reserved.
See omnystudio.com/listener for privacy information.

Are you still training like you did in your 20s, going hard every session and wondering why recovery takes so much longer than it used to?
This is one of the most listened-to episodes of the Triathlon Nutrition Academy podcast, back by popular demand. I sat down with coach Joe Friel, co-founder of TrainingPeaks and author of Fast After 50, to talk about how masters triathletes can stay fit, fast and injury-free in their 40s, 50s and beyond. Joe covers the training side and my Ep 178 on key nutrients for masters triathletes covers the nutrition side, so listen to them as a pair.
WHAT YOU’LL LEARN
What actually changes in your body as you age, and the one marker that holds up surprisingly well
Why rest and recovery become your biggest performance lever after 40
The 5:2 training week Joe uses with masters athletes (plus the nine-day alternative)
Where strength and mobility fit into a busy training week, and the session you should never lift weights before
How to use heart rate variability to decide when to train hard
TIMESTAMPS
00:00 Introduction
02:00 Training as a masters triathlete
04:09 How your physiology changes after 40
09:18 Why rest and recovery matter more with age
11:21 The nine-day week vs the 5:2 training week
14:28 The tortoise, the hare and the lactate myth
19:27 Mobility and strength training for masters athletes
28:57 Why you should never lift weights before a run
30:48 Recovery weeks, testing and the off-season
35:11 Using HRV and wearables to guide training
39:00 Daily habits for longevity in the sport
42:24 Joe’s number one piece of advice
ABOUT JOE FRIEL
Joe Friel has coached endurance athletes for more than four decades. He is a co-founder of TrainingPeaks and the author of Fast After 50, a go-to resource for athletes who want to keep performing as they age. Connect with Joe
RESOURCES MENTIONED
Fast After 50 by Joe Friel
HRV4Training app
Ep 178: Key Nutrients for Masters Triathletes
Ep 179: the original release of this episode
READY TO STOP GUESSING WITH YOUR NUTRITION?
The Triathlete Fuel Kit brings together my Triathlon Nutrition Kickstart course, the Triathlete’s Kitchen recipe database and the Fuel Your Adventure recipe book, so you can get your everyday fuelling working for you, not against you. Get the Triathlete Fuel Kit
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The Triathlon Nutrition Academy® is a podcast by Dietitian Approved®. All rights reserved.
See omnystudio.com/listener for privacy information.

Why is your triathlon nutrition strategy still not working when you already know what to do?
I asked the triathletes who just finished my Triathlon Fuel Camp what they had spent money on to improve their performance. 70% had paid for a bike fit, 66% had a coach and 50% had bought a power meter and faster wheels. Only 20% had ever invested in a dietitian or nutritionist, and 57% told me they were winging their nutrition. These are smart, driven athletes with more information at their fingertips than any triathlete in history. So why is it still not working?
IN THIS EPISODE, YOU WILL LEARN:
Why more information is not what is missing from your nutrition
What a strategy specific to you is actually built on (and why generic advice never holds for long)
The 3 ways triathletes try to build a nutrition strategy, and the only one that lasts your whole racing life
The 3 questions that keep triathletes on the precipice of dialling in their nutrition for years
How Kelly, Steve and Julia from the Triathlon Nutrition Academy finally got off the fence
TIMESTAMPS
02:02 Why your triathlon nutrition strategy isn't working
10:15 3 questions holding triathletes back
EPISODES MENTIONED
Episode 235 with Julia
Episode 237 on why DIY nutrition is not working
Episode 259 with Kelly and the TNA crew at the 70.3 World Championship in Nice
Episode 261 with Steve, Curt and Jade
READY FOR A STRATEGY THAT IS SPECIFIC TO YOU?
The Triathlon Nutrition Academy is my 9-month program where I teach you how to fuel your own training and racing, step by step, with an Advanced Sports Dietitian checking your work along the way. Find out more about the Triathlon Nutrition Academy here.
SUPPORT THE PODCAST HERE
CONNECT WITH TARYN
Website | Instagram | Facebook | YouTube
The Triathlon Nutrition Academy® is a podcast by Dietitian Approved®. All rights reserved.
See omnystudio.com/listener for privacy information.