Do You Need 120 Grams of Carbs Per Hour? Sodium Bicarb? New Running Nutrition Research Review
Tread Lightly Running Science PodcastSummary
Recent discussions in the running community focus on two popular fueling trends: the intake of 120 grams of carbohydrates per hour during marathons and the use of sodium bicarbonate as a supplement for endurance performance. A study published in the Journal of Applied Physiology highlights that elite male marathoners who consumed 120 grams of carbs per hour showed improved running economy but also experienced significant gastrointestinal distress. This raises questions about the practicality of such high carbohydrate intake for most runners, as it requires extensive gut training to avoid nausea and cramping.
In contrast, a systematic review of sodium bicarbonate's effectiveness for distance running indicates negligible benefits for performance, particularly in races longer than 15 minutes. While some elite athletes report positive effects, the study found that gastrointestinal issues, such as nausea and diarrhea, significantly limit its use for recreational runners. The analysis suggests that instead of relying on supplements, athletes should focus on consistent training and proper carbohydrate intake, with recommendations of 60 to 90 grams of carbs per hour for optimal marathon performance.
Overall, these findings emphasize the importance of individualized fueling strategies and the need for further research to clarify the efficacy of these popular trends in the broader running community.
Show Notes
Do you need 120 grams of carbs per hour? Will adding sodium bicarb to that further boost performance? In this episode, we take a deep dive into two trending studies on sport nutrition and running performance. We chat about high carb fueling, sodium bicarb supplementation, practical applications from these studies, and some nuance around study structures, sample sizes, author biases, and more. Hopefully by the end, we’ve saved you both some money and some unnecessary mid-race bathroom breaks.
In this episode, you’ll learn about: 🔸 If you should fuel with 120 grams of carbs per hour 🔸 Whether carbs help with fatigue or its all in your head 🔸 How to use high carb fueling in your marathons 🔸 If bicarb is as effective for long-distance running as marketing claims
Tread Lightly Running is hosted and researched by Amanda Brooks and Laura Norris, MSc. Production, show notes, and graphics by Laura Norris. Media kit available to interested sponsors upon request.
References: 🔬PMID: 41416636 🔬PMID: 41191077 🔬PMID: 39786965 🔬PMID: 40089940 🔬PMID: 32403259
If you enjoyed this episode, you may like: 🎧 What You Really Need to Know About Fueling Your Runs (28 Nov 2025) 🎧 What Running Economy Really Means for Your Performance with Dr. Shalaya Kipp (31 Oct 2025) 🎧GLP-1s, Nomio, UCAN Gels, and Other Trendy Supplements with Dietitian Alex Larsen (18 Sept 2026)
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