When it comes to fuelling endurance exercise such as cycling and running, gels, chews and sports drinks are usually the first things that come to mind. They’re evidence-based carbohydrate (CHO) sources, easy to carry, and provide a reliable amount of carbohydrate. But they aren’t the only option. Athletes are increasingly moving towards cost-effective whole food options for

CHO ingestion to ensure optimum performance. So does choosing a whole-food over a sports product have any effects on performance? And do they cause any gastrointestinal (GI) symptoms?

Why Carbohydrate is Needed During Endurance Exercise

Carbohydrate is an important fuel source during endurance exercise, particularly as the intensity increases. It is predominantly stored as glycogen in skeletal muscle and the liver, with smaller amounts circulating in the blood. However these stores are finite, meaning that carbohydrate availability becomes an increasingly important factor as exercise continues for extended periods as glycogen depletion is considered a limiting factor of performance. The rate at which glycogen is used also depends on various factors such as exercise intensity and duration, starting glycogen concentration, the individual’s training status, and which muscles are being used.

The American College of Sports Nutrition (ACSM) 2016 guidelines gave the following recommendations:

• Less than 60mins = no carbohydrate intake
• 1-2.5 hours = 30-60g of rapidly oxidised carbs (e.g. glucose)
• 2.5-3 hours = up to 90g per hour, utilising multiple carbohydrate sources (e.g. 2:1 ratio of glucose to fructose) to enhance absorption and prevent GI distress

Whole Foods vs Sports Nutrition: Does the Source of the Carbohydrate Matter?

Further research from Viribay et al (2020) found that elite mountain marathon runners consuming higher amounts of carbohydrate (around 120g/hr) experienced significantly less exercise-induced muscle damage and improved recovery. However this study was small and involved elite male athletes who had specifically trained their gut to tolerate high levels of carbohydrate intake, so it is hard to extrapolate these findings to the average athlete. The goal is not to consume the greatest amount of carbohydrate possible, but to consume enough to support performance without compromising comfort or practicality. This raises the important question of does it matter whether the carbohydrate source comes from gels and sports drinks, or could whole foods be equally effective?

There are many reasons why an athlete might consider whole food options, they can be cheaper, more accessible and more familiar than specialist sports nutrition, while also providing additional nutrients. They can also offer more variety when it comes to taste and texture, which can become increasingly important during longer events.

Are Whole Foods as Effective as Sports Nutrition When It Comes to Performance?

Whole food fuelling options include:

• Bananas
• Raisins
• Dates
• Honey
• Rice cakes
• Potatoes
• Oats
• Rice
• Pasta

One of the main points here is that not all whole foods are equally practical during exercise, as foods that are bulky, high in fibre, or difficult to carry can be a challenge to consume during exercise.

One study by Too et al (2012) compared raisins with commercial carbohydrate chews during 80 minutes of running followed by a 5km time trial. Both carbohydrate conditions resulted in faster 5km performance than water, with no significant difference between raisins and chews. GI symptoms were also mild and did not significantly differ between the two sources.

Gastrointestinal Symptoms and Gut Training

Similar findings have been seen with bananas. Nieman et al (2023) compared bananas with a 6% carbohydrate sports drink during a 75km cycling time trial, with carbohydrate intake matched between conditions. Performance and blood glucose responses were similar, suggesting whole food sources can provide an effective alternative to a conventional sports drink. However participants reported greater feelings of fullness and bloating when consuming bananas, which while this didn’t impair their performance in this study, it could become relevant when an athlete needs to consume larger amounts of carbohydrate over many hours or during other activities such as running due to the increased stress placed on the GI system.

These findings suggest that the body does not necessarily require a specific sports nutrition product to use carbohydrates effectively. If an athlete can consume sufficient carbohydrate from whole food sources such as those discussed, there is no inherent performance disadvantage. However as carbohydrate targets increase, the practical advantage of gels, drinks and chews becomes more apparent. Leading into the next question you might be asking, will whole foods lead to unwanted gastrointestinal symptoms?

Are Whole Food Options More Suited to Specific Events?

Gastrointestinal distress is one of the biggest concerns when it comes to whole-food fuelling. GI symptoms can unfortunately be all too common during endurance exercise and can include nausea, bloating, abdominal pain and cramping. Importantly though, these symptoms are not always caused by food alone and can be due to exercise duration, heat, hydration status, and reduced blood flow to the gastrointestinal tract. Commercial gels and drinks are specifically formulated to contain a predictable amount of carbohydrate, delivering it in a small volume with relatively little fibre, fat or protein which can be advantageous when running at high intensities. Whole foods are more complex. A banana for example provides carbohydrate along with water, fibre, and other nutrients which increase the volume of the food that needs to be consumed, and may slow gastric emptying leading to some of the side effects described previously. Fortunately, GI tolerance is not necessarily fixed, and repeatedly practising carbohydrate consumption during training (often referred to as ‘gut training’) appears to improve the ability to tolerate carbohydrates during exercise.

Take Home Message

The practical takeaway from this is therefore to train the gut to become familiar with consuming whole foods during training. Experiment with the amount, timing and type of carbohydrate you intend to use during the race. If whole foods work for you, there is no physiological reason to replace them with gels, and equally if consuming large amounts of solid food causes fullness or discomfort, gels or drinks can help you more easily achieve your carbohydrate target.

References

The idea of gut training also links into the question of whether whole foods are more suited to specific races such as ultramarathons. For a road marathon, intensity is relatively high and there may be limited opportunities to eat, with most aid stations only providing gels and sports drinks. Therefore in this situation gels and carb-based drinks can be advantageous due to their compact and predictable nature. For something like an ultramarathon, the situation can be quite different. Events can last many hours or even days, intensity is often lower, and runners have considerably more time to consume food, with aid stations being more likely to stock whole food options such as bananas and oat bars. Taste fatigue can also become an issue when consuming sweet gels and drinks for an entire day. This makes whole foods very useful as additions to a fuelling strategy. The optimal strategy is likely to change with the demands of the event, how well-trained the gut is, and what will provide enough carbohydrate comfortably and consistently for the duration of the event.

Ultimately, there is no single ‘best’ fuelling strategy. Whole foods and sports nutrition can both be effective sources of carbohydrate, and the best choice depends on the event, your carbohydrate needs, GI tolerance and personal preference. The key is to find what works for you, and this may be a combination of the two – just make sure to practise it before race day!

• Jeukendrup, A. (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine, 44(Suppl 1), 25–33.
• Viribay, A., Arribalzaga, S., Mielgo-Ayuso, J., Castañeda-Babarro, A., Seco-Calvo, J., & Urdampilleta, A. (2020). Effects of 120 g/h of carbohydrates intake during a mountain marathon on exercise-induced muscle damage in elite runners. Nutrients, 12(5), 1367.
• Too, B. W., Cicai, S., Hockett, K. R., Applegate, E., Davis, B. A., & Casazza, G. A. (2012). Natural versus commercial carbohydrate supplementation and endurance running performance. Journal of the International Society of Sports Nutrition, 9(1), 27.
• Nieman, D. C., Gillitt, N. D., Henson, D. A., Sha, W., Shanely, R. A., Knab, A. M., … & Jin, F. (2012). Bananas as an energy source during exercise: a metabolomics approach. PLoS One, 7(5), e37479.
• Martinez, I. G., Mika, A. S., Biesiekierski, J. R., & Costa, R. J. (2023). The Effect of Gut-Training and Feeding-Challenge on Markers of Gastrointestinal Status in Response to Endurance Exercise: A Systematic Literature Review: IG Martinez et al. Sports Medicine, 53(6), 1175–1200.

ABOUT THE AUTHOR

Isabel holds a BSc in Human Biology and is an aspiring sports nutritionist wanting to bridge the gap between academic research and athletic performance. She enjoys delving deep into the research to help inform others and has a passion for running, having completed multiple half marathons and marathons. She is now looking to move into ultrarunning and share helpful research along the way.