One of the most common questions I get asked by runners is how to fuel during long runs when you don’t feel like eating anything. Many find that drinking a sports drink or eating food makes them feel like throwing it straight back up. Do you also struggle fuelling during races? Well, you’re not alone – fuelling on the move can prove tricky for many. It can make you feel bloated, uncomfortable, queasy and even trigger vomiting or diarrhoea.
As result, many endurance athletes prefer training on ‘empty’, shunning fluid at aid stations and forgoing fuel during races for fear of unplanned toilet stops. But when you’re exercising at high intensities and competing for longer than 60 – 90 minutes, this strategy can quickly lead to dehydration, reduced endurance and perhaps not even finishing the race. Quite a conundrum.
Fortunately, there is a solution: ‘gut training’. Sports scientists say that the gut is very adaptable. This means that it can respond to nutritional training during exercise. In other words, you can literally train your gut – much like any other muscle in your body – to tolerate and absorb more carbohydrate while exercising. There’s not been a great deal of research on the topic but this excellent review by Asker Jeukendrup provides a neat summary.
What’s required is a gradual and consistent approach to fuelling and drinking on the move. The idea is to start with small quantities and increase slowly over time. With practice, your stomach will learn to accommodate a greater volume of fluid and food and empty faster so you start to feel less full and uncomfortable whilst exercising.
By focusing on carb-rich foods and drinks, you’ll also train your gut to absorb carbohydrates more efficiently. This increases the number and activity of glucose transporters in the gut, allowing greater carbohydrate absorption and utilisation during exercise.
Normally the gut can only absorb a maximum of 60g per hour. Any more than this just sits ‘heavy’ in the stomach. But by gradually increasing the amount of carbs you consume during exercise and by consuming a mixture of glucose (or maltodextrin) and fructose (such as an energy drink), you can train your gut to absorb up to 90g per hour. This would be beneficial when you’re exercising at high intensities for longer than 2 hours.
How long will it take to train your gut? Like most things in nutrition, it’s very individual. Some people adapt quicker than others but you can expect a significant improvement within a few weeks. Here’s how to train your gut for workouts longer than 60 – 90 minutes
- Gradually increase the amount of fluid you consume during exercise – little and often works best. Start with just a couple of sips pre- and mid-workout, then increase gradually as you become accustomed to the sensation of fluid in your stomach.
- Experiment with different food options to discover which foods or products your body can tolerate. Try a couple of bites of banana, a Medjool date, an energy ball (such as these Energy Balls) or a bite of energy bar. Other options include fruit bars, jelly babies, energy gels, plain biscuits, rice cakes or fig rolls.
- Begin refuelling after 30 or 60 minutes, then aim for 10 – 15g carbs every 30 minutes. Do this for each long workout (> 90 minutes). Once this feels okay, up the quantity or add another mid-workout ‘feed’. Over time your stomach will learn to accept bigger volumes and empty faster, so instead of feeling full and bloated, you’ll feel comfortable.
- When preparing for a big race, it’s important to practise your fuelling plan during training. Take the same foods and drinks that you plan to use in the race. It may take quite a bit of trial and error so try to do this early in your race preparation programme. Don’t leave it to race day!
Being able to train your gut this way will give you a huge advantage for training and races longer than two hours. It means that you’ll be able to stay fuelled, cut the risk of getting gut problems and ultimately improve your performance.
If you’re looking for some easy and tasty inspiration on how to include more plant foods in your diet, then The Vegetarian Athlete’s Cookbook – More than 100 recipes for active living (Bloomsbury, 2016) is a great place to start. It features:
More than 100 delicious, easy-to-prepare vegetarian and vegan recipes for healthy breakfasts, main meals, desserts, sweet and savoury snacks and shakes.
- Expert advice on how to get the right nutrients to maximise your performance without meat
- Stunning food photography
- Full nutrition information for each recipe, including calories, carbohydrate, fat, protein and fibre