INSIDE SPORTS NUTRITION

Do you need a higher (> 60 g/h) carb (CHO) intake rate?

Will it result in better performance?

If the duration of your event is long enough to warrant higher CHO intake, the biggest question to ask yourself is “how do I feel” and to determine if you experience any GI symptoms (e.g. uncomfortable fullness, bloating, GI cramping, gas, diarrhea, nausea etc.) with different CHO strategies. If you have any of these symptoms, especially under “race conditions”, a gut training protocol may help to improve your CHO tolerance during exercise. 

GI symptoms are a frequent indicator of incomplete digestion, absorption, and utilization of the exogenous CHO. These symptoms with higher CHO intake rates are more often observed in newer, recreational or relatively untrained individuals in comparison to experienced or elite athletes. Following a low CHO diet can also cause low CHO tolerance during exercise. However, with some intentional practice and adjustments, the gut can be trained to tolerate more CHO. 

Interestingly, not all athletes who undergo gut training will actually increase whole body CHO utilization rates, yet performance can be significantly improved following two weeks of successful gut training, with a decrease in GI symptoms. Reduce GI symptoms + Increase CHO = you feel better so you go faster! 

So how is gut training best executed?

1. Give yourself at least two weeks to complete an individualized protocol that includes at least 2-3 days per week of gut training, in sessions that mimic event specificity.
2. Find your limit of CHO and fluid intake per hour using the actual products (food and drink) you would plan to use during the event – the limit would be when you start to experience upper or lower GI symptoms.
3. Train with 100-120% of this CHO and fluid intake and keep notes from each session, refining each day as needed.
4. Consider some of the following factors that may influence your protocol: volume of fluid, concentration of fluid, frequency of intake, type of CHO, your regular diet (e.g. FODMAP content, amount of dietary CHO), heat/humidity in environment, hydration status, fat/fiber content of your fueling plan etc. 
5. To compensate for the stress of race day, consider using 80% of your CHO and fluid intake tolerance to decrease the risk of GI symptoms.

PMID: 35963615, 34557109