How to train your gut
Just like we can train our muscles or heart to adapt and improve performance, we can train our gut as an athletic organ to improve our performance too.
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Gut training is a sports nutrition strategy that can be really helpful for athletes who suffer from gut upsets or irritations; are wanting or needing to take on more fluid and carbohydrate during exercise, or are needing to tolerate more food / nutrition before and after exercise.
So, let’s dive into the details and see how you can implement this into your training.
Improve gastric emptying and absorption and likely reduce the chances and/or severity of GI problems, thereby improving endurance performance as well as providing a better experience for the athlete (Jeukendrup, 2017).
Aka. Allow the gut to adjust to (more) nutrition in and around exercise, to then improve performance.
Takes 2-4 weeks of regular training for gut to adjust
Start small and build
Trial in lower intensity sessions and then move into higher intensity and longer sessions (e.g. start in a recovery run and then trial in interval/tempo/threshold run)
Practice nutrition strategies and train your gut in race / competition conditions - ie. in the heat or in the cold as these can affect your gut, carbohydrate oxidation and digestions + absorption.
OPTION 1: Start small and build
If you are wanting to get used to eating before training/ events: try something smaller and plainer (lower fibre, lower fat), 30-60 minutes before
½ - 1 Banana
Slice of toast/ bread with or without spread
Plain crackers/ rice or corn thins
Easy to eat muesli bar or ½ clif bar
½ cup juice
Once you are comfortable with this and no issues, build.
Add banana to slice toast ± honey or maple syrup etc
Rice thins or crackers with honey or banana
Juice and a muesli bar
Smoothie or up & go
Then practice in event specific sessions. Practice the timings too. For example, if you will eat an hour before your event, do that. If you will eat 3 hours before, try practice that too.
You can also do this for post training fuel. If you struggle to eat after exercise:
Start small and often (as gastric emptying can be slowed down, so you can’t handle as much food!)
Go plain (lower fibre, lower fat, no heavy meats or deep fried foods)
Go liquids instead of solids: smoothie, juice, protein shake, yoghurt, soups etc
Start with carbohydrate and protein. Then add more colour for fibre and quality fats
Build the meal as you adjust
OPTION 2: During nutrition
If you’re training for an event that’s less than 2 hours, start at 30g of carbohydrate per hour. If you’re training for an event over 3 hours, start at 40-50g per hour,
If you prefer liquids, start with carbohydrate containing sports drinks and also water. Then once you can tolerate this, add in gels/lollies/ bloks/ bars. After this, solids.
Practise and trial this in aerobic, lower heart rate sessions. Then build into efforts, tempo and race specific sessions.
Once you can tolerate this amount, increase it if you need.
For example, if you’re faster and leaner, you may benefit from 60-90g of carbohydrate per hour (for marathons, long distance triathlons, marathon swims, and ultra triathlons and ultra runs)
You can do this by adding more fructose based products and a mix of solids and liquids
Do fluid testing to know how much fluid you need to aim for. This will take practice too and gut training too!
Improved gastric emptying into the intestine = improved carbohydrate absorption
Improved tolerance to nutrition and fluids = possibly less gut upsets
Reduced gastrointestinal symptoms such as bloating, gas, reflux, diarrhoea, exercise-induced IBS,
Reduced time to fatigue
Improved performance and recovery
Some of these still have mixed results in research studies, however they could be possible benefits for you.
Fig 3 schematic illustration of gut training benefits - The Effect of Gut-Training and Feeding-Challenge on Markers of Gastrointestinal Status in Response to Endurance Exercise A Systematic Literature Review. I. G. Martinez et al. 2023.
So, my challenge to you - spend the next month (4 weeks) training your gut to either take on food before training or to take on more fluid and carbohydrate during. Keep track of what you try, what works, and how you feel.
Happy training and eating,
McCubbin, A. & Gaskell, S. 2022. The Long Munch. [Podcast]. 20 July 2022.
I. G. Martinez et al. 2023. Sports Medicine https://doi.org/10.1007/s40279-023-01841-0