UCI Sports Nutrition Project: Nutrition in road cycling

The recently published UCI Sports Nutrition Project paper on road cycling provides one of the most comprehensive overviews to date of race nutrition in professional road cycling (1)(CLICK HERE). It was a privilege to bring together a group of scientists and practitioners working directly with WorldTour teams, to write a scientific paper and describe evolution or revolution of nutrition in this sport that is leading the way in applied sports nutrition. This paper aimed not to simplify, but to critically examine the science and its application and this blog will summarise the most important aspects of the UCI paper.

The changing sport of cycling: implications for metabolism and nutrition

Modern professional cycling is characterised by an increase in race intensity, particularly in the early phases of races. Analysis of power output distributions shows that although a large proportion of time is still spent below lactate threshold, decisive moments occur at very high intensities. In the past, races often started conservatively and the finals were very high intensity. In recent years, the racing has become more aggressive with higher power outputs (and speeds) earlier in the race. Teams deliberately increase the pace early in the race to create fatigue and force selection.

This has two key metabolic consequences. First, glycogen depletion may begin earlier in the race. Second, the reliance on exogenous carbohydrate increases. Traditional models of “saving energy for the finale” are still applicable but have become more challenging in current race scenarios. From a physiological perspective, this reinforces the central role of carbohydrate availability in maintaining performance, particularly when repeated high-intensity efforts are required (2, 3).

Energy expenditure and the limits of estimation during cycling

Energy expenditure in professional cycling has been well documented using doubly labelled water and power-based estimations (4, 5). Values of 5,000–7,000 kcal/day are common, with extremes exceeding this during mountain stages. The use of power meters, the collection of data, and the fact that teams now have access to vast amounts of historical data makes it possible to come up with reasonable predictions of energy expenditure for difference races or stages. This information is then used to dial in daily nutritional intake. It then becomes a balancing game. Riders do not want to gain weight as this would mean a performance disadvantage going uphill and riders don’t want to lose weight as this would likely mean they are underfueled and or losing muscle mass. And during stage races, incomplete recovery and net muscle breakdown will have knock-on effects in the following days. So maintaining energy balance is critical.

Glycogen stores are important, but extreme protocols are not necessary

The physiological basis for carbohydrate for endurance exercise is well established. Carbohydrates provide a higher ATP yield per unit of oxygen compared to fat, making them the preferred substrate at higher intensities (6, 7). Low glycogen stores have been associated with decreases in performance, but in cycling the concept of glycogen loading in the traditional sense is not really applicable.

Glycogen loading is not about eating as much as possible, it is about making sure glycogen stores are full.

Well-trained cyclists should be able to restore glycogen within 24 hours with appropriate nutrition. Classical glycogen loading protocols such as those applied by runners and triathletes are less relevant in cyclists who train or race almost daily. It is more a matter of restoring glycogen fully post-exercise on a daily basis. For longer one-day races (for example, monuments), it is not too different as high or very high glycogen stores are unlikely to make a difference. This is because supramaximal glycogen stores will accelerate the breakdown of glycogen. A common mistake is still confusing carbohydrate loading with overeating…. It is not about eating as much as possible, it is about making sure glycogen stores are full.

From 30 g/h to 120 g/h during cycling: evidence to practise

One of the most striking developments is the increase in carbohydrate intake during exercise. The shift from ~30 g/h to 90 g/h was strongly supported by studies demonstrating higher exogenous carbohydrate oxidation with multiple transportable carbohydrates (8, 9). More recently there are reports of much higher intakes by athletes but this is mostly based on an idea that if a lot of carbohydrate is good, then more must be better.

However, the current reality is that a move towards 120 g/h and beyond is less well supported. Studies show increased exogenous oxidation at higher intakes but performance data are limited. We did studies already in 2005 with 144 g/h (8) but we went back to more realistic advice of 90 g/h because physiologically there seemed to be no further advantage, whilst at the same time the risk of developing gastro-intestinal (GI) problems increased. In those days few athletes “trained the gut” and the drinks used were probably not as good as some of the products we currently have on the market, so GI problems 20 years ago were probably more likely to occur than now.

Fuel for the work required: beyond guidelines

The concept of “fuel for the work required” reflects a shift from static recommendations to dynamic, context-driven strategies (10). To a large part this happens automatically. When the energy expenditure is high, riders would naturally eat more but there is also a tendency to overeat on rest days, and undereat on the really hard days and this is the main reason why teams employ nutritionists to manage energy balance better. In cycling, this is particularly relevant due to large variability in daily demands. Carbohydrate intake may range from 5 to >20 g/kg/day depending on workload.

However, implementing this concept requires:

• Estimating energy and carboydrate needs.

• Accurate assessment of workload.

• Understanding of substrate utilisation.

• Integration with recovery and multi-day planning.

Importantly, this approach challenges traditional daily macronutrient targets. Instead, it emphasises prioritisation: protein as a constant, carbohydrate as variable, and fat as flexible. Teams use software solutions to help deliver this at scale.

Protein and concurrent nutrient interactions

Protein ingestion is critical for recovery and adaptation, primarily through stimulation of muscle protein synthesis (11). However, protein ingestion during exercise does not appear to enhance protein synthesis in active muscle (12). Furthermore, protein may impair gastric emptying, potentially reducing carbohydrate delivery during exercise. This creates a trade-off between immediate performance and longer-term recovery. In practice, most teams prioritise carbohydrate during exercise and protein post-exercise.

Hydration strategies

Hydration strategies in cycling are influenced as much by logistics as by physiology. Sweat rates can vary from 0.6 to 2.0 L/h or more, but opportunities to drink are constrained by race conditions and access to bottles. Therefore, hydration strategies must consider both physiological and contextual factors, rather than relying on fixed thresholds.

Body mass management

The importance of power-to-mass ratio in cycling is well established. Small reductions in body mass can significantly improve climbing performance. However, there is increasing recognition of the risks associated with aggressive weight management, including low energy availability and impaired performance.

The optimal approach involves:

• Periodised body composition targets.

• Moderate energy deficits.

• Maintenance of carbohydrate availability.

Short-term strategies such as low-fibre diets may be used, but require careful implementation.

Practise ahead of evidence

A recurring theme is that practice in professional cycling is, in some areas, ahead of the published evidence. This is not unusual in elite sport, where marginal gains are pursued aggressively. As an example, the predictions of the energy and carbohydrate needs cannot be found in the scientific literature, but teams have their own ways to calculate these (some will use existing applications containing algorithms that are not in the public domain, others are using trained AI engines to get to accurate predictions). Future work should focus on bridging the gap between laboratory findings and real-world application.

Summary

The UCI Sports Nutrition Project highlights a fundamental shift in race nutrition. The underlying physiology has not changed, but its application has become more precise, individualised, and integrated. For practitioners, the challenge is not simply understanding the science, but applying it effectively within the constraints of racing.

Ultimately, nutrition in cycling is no longer just about fuelling. It is about decision-making under uncertainty, integrating physiology, logistics, and strategy into a coherent performance system. The recommendations are usually not the problem. It is turning those recommendations into successful practices and behavior change. This requires a team to come together and is not just a nutritionists job or a chefs job.

References

1. Jeukendrup, A.E., Redegeld, M., Martins, G., Whitfield, J., Burke, L.M., Mujika, I., Dolan, E., & Gonzalez, J.T. (2026). UCI Sports Nutrition Project: Race Nutrition for Road Cycling. International Journal of Sport Nutrition and Exercise Metabolism, 36(3), 215-232.

2. Coyle, E.F., Coggan, A.R., Hemmert, M.K., & Ivy, J.L. (1986). Muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate. Journal of Applied Physiology, 61(1), 165–172.

3. Jeukendrup, A.E. (2011). Nutrition for endurance sports: Marathon, triathlon, and road cycling. Journal of Sports Sciences, 29, S91–99.

4. Saris, W.H., van Erp-Baart, M.A., Brouns, F., Westerterp, K.R., & ten Hoor, F. (1989). Study on food intake and energy expenditure during extreme sustained exercise: The Tour de France. International Journal of Sports Medicine, 10, S26–S31.

5. van Hooren, B., Cox, M., Rietjens, G., & Plasqui, G. (2023). Determination of energy expenditure in professional cyclists using power data: Validation against doubly labeled water. Scandinavian Journal of Medicine & Science in Sports, 33(4), 407–419.

6. Frayn, K.N. (1983). Calculation of substrate oxidation rates in vivo from gaseous exchange. Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology, 55(2), 628–634.

7. van Loon, L.J.C., Greenhaff, P.L., Constantin-Teodosiu, D., Saris, W.H.M., & Wagenmakers, A.J.M. (2001). The effects of increasing exercise intensity on muscle fuel utilisation in humans. Journal of Physiology, 536(1), 295–304.

8. Jentjens, R.L.P.G., & Jeukendrup, A.E. (2005). High rates of exogenous carbohydrate oxidation from a mixture of glucose and fructose ingested during prolonged cycling exercise. The British Journal of Nutrition, 93(4), 485–492.

9. Currell, K., & Jeukendrup, A.E. (2008). Superior endurance performance with ingestion of multiple transportable carbohydrates. Medicine & Science in Sports & Exercise, 40(2), 275–281.

10. Impey, S.G., Hearris, M.A., Hammond, K.M., Bartlett, J.D., Louis, J., Close, G.L., & Morton, J.P. (2018). Fuel for the work required: A theoretical framework for carbohydrate periodization and the glycogen threshold hypothesis. Sports Medicine, 48(5), 1031–1048.

11. Gorissen, S.H.M., Rémond, D., & van Loon, L.J.C. (2015). The muscle protein synthetic response to food ingestion. Meat Science, 109, 96–100.

12. Beelen, M., Zorenc, A., Pennings, B., Senden, J.M., Kuipers, H., & van Loon, L.J.C. (2011). Impact of protein coingestion on muscle protein synthesis during continuous endurance type exercise. American Journal of Physiology, Endocrinology and Metabolism, 300(6), E945–E954.