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ToolBox
Toolbox: Stage Racing Nutrition
With the 2017 Vuelta a España starting on Saturday for the pros and that now is the season for big summer rides for the rest of us. How does one fuel these big efforts, and how good are we at maintaining energy balance throughout multiple days of hard riding?


One-day classics are fabulous because of their "no tomorrow" nature, with every rider putting it all on the line for that one single day. Stage racing, however, is a pretty amazing physiological effort for cyclists because of the high demand on recovery in a very short period of time. This recovery takes many forms, from metabolic to neuromuscular to thermoregulatory to psychological.

A fundamental aspect of recovery is nutritional. Due to the intensity and the prolonged duration of effort during the race itself, coupled with the limited capacity to ingest and absorb nutrients due to reduced blood flow in the gastrointestinal system, it is almost impossible to match caloric intake to output during the race itself. So from the moment that they cross the line, riders have anywhere from 16 to 18 hours – including sleeping hours – to replace all of the calories that were burnt over the course of the race.



Saris et al. 1989
The classic study concerning cycling stage races and energy balance was published in 1989 by Dutch scientists following 5 riders during the Tour de France (Saris et al. 1989). They reported a fairly good match between energy expenditure (mean 25.4 MJ, peak 32.7 MJ) and mean energy intake (mean 24.7 MJ, peak 32.4 MJ), along with a relative contribution of carbohydrates, fat, and protein of 62, 23, and 15% total energy intake, respectively. Also, approximately 49% of energy intake occurred during the race itself, with a large majority (94 g an hour, 69% of total energy intake) in the form of carbohydrates.

Rehrer et al. 2010
A few years back, I wrote about a 2010 New Zealand study tracking four elite cyclists during the 10 stage, six day Tour of Southland race (Rehrer et al. 2010). There again, energy intake (27.3 MJ/d) closely matched energy expenditure (27.4 MJ/d). Despite advances in sports nutrition technology and availability of supplements such as drinks, gels, and energy bars since the 1989 study, only 20% of total caloric intake was in the form of supplements. I found it interesting that the 1989 study reported that 49% of energy intake occurred during the race, yet here less than half of the intake during races itself was in the form of supplements. This would suggest that, while such energy products certainly have their place in terms of ease of use, athletes remain partial to the palatability of real food.

The Racing Weight Loss Plan
We sometimes hear stories of pro using a block of racing to become race fit and to work their way into shape. Sometimes this includes implications that racing is being used to help slim down and drop weight. Does this actually happen in reality? Is the intense nature of racing really amenable to sustaining a caloric deficit necessary to reduce weight? What are some of the body composition changes that accompany a stage race?

The New Zealand study used a combination of the calibrated scale and also a DEXA body scanner to quantify and track changes in body composition. Data from the scale, taken each morning upon waking and after voiding, showed minimal changes in body weight each day over the six days. The body scanner was used three days before the race start and again one to two days after the race ending. Here, one subject was measured as losing approximately 3 kg of weight, with approximately 300 g of lean mass loss and the remainder in the form of fat. The other three riders appeared to show minimal changes using the body scanner.

Sánchez-Munoz et al. 2016
A third study tracking high-level cyclists during stage racing has just been added to the literature. Published just this month in the Scandinavian Journal of Medicine and Science in Sports, this Spanish study tracked six professional riders from the Andalusia-Cajasur Continental team during the 2009 Tour of Andalusia (Sánchez-Muñoz et al. 2016).

The six cyclists were obviously highly trained, training on average 20 to 25 hours weekly and accumulating 21,000 to 25,000 km annually. The four stages covered 647.6 km over the course of four days, including what appeared to be two flattish stages mixed with two hillier stages. While this tour may rank relatively low compared to the Tour de France, keep in mind that this would be one of the biggest events of the season for a Spanish Continental team, especially for a team from the home region.

Being an early-season race, the weather was relatively cool, with minimum temperatures of 6°C and a maximum of 20°C. Average power output was 246 Watts, while heart rate averaged 134 bpm. Typical of professional cyclists, they were relatively very lean, at 176 cm in height and 67.6 kg in mass on average.



What’s in the (Data) Mussette?
In case you are wondering why such nutritional tracking studies are so rare, keep in mind the incredible logistical challenges involved for the scientists. Not only is following and supporting a stage race hard enough for anybody, the scientists had to analyse, track, and weigh all food and drink taken in for the entire duration of the race for all the riders.

• Supporting the prior studies, macronutrient intake was primarily carbohydrates for each of the six days, averaging 868 g daily, or 62.3% of total energy intake. Fats and proteins were 145 (23.2%) and 201 (14.5%) grams daily, respectively. This pattern held over each of the six days, with only day #4 dipping below 60% total energy intake from carbohydrates (58%). Mean energy intake was 5,644 kilocalories per day.

• Daily carbohydrate intake worked out to 12.8 g/kg for the cyclists. This is slightly above the high end of 12.0 suggested for maximizing muscle glycogen stores for cyclists undertaking two hours of daily training, but remains within a relatively normal range for ultra endurance athletes. Translating the Tour of Southland and the Tour de France data, the daily intake of those cyclists was 12.9 and 12-13 g/kg, respectively.

• Protein intake worked out to 3.0 g/kg daily. This exceeds common recommendations for endurance and strength athletes of approximately 1.2 to 1.7 g/kg, but again matches the data from the Tour of Southland (2.9 g/kg). It remains unknown at present whether this higher than normal protein intake is required to aid with palatability and satiety, or also whether this may aid in glycogen recovery.

• Similar to the New Zealand data, no significant overall body mass changes were observed for the cyclists. However, there was a significant reduction in fat mass with no changes in muscle mass. This appears to support the idea that higher aerobic capacity results in primarily the use of fat stores for metabolism, and that it may be possible to use prolonged hard intensity training periods or races did decrease fat mass in endurance athletes.

• Analyses were also made of the micronutrient intake over the four-day race. Overall, all micronutrients exceeded RDI recommendations, with the exception of folate and potassium. While it remains unclear whether micronutrient intake needs to be increased above the RDI in light of a heavy energy output, this study suggest that the careful monitoring of micronutrients might be important during prolonged heavy exertion.



Summary
There is a lot to learn from studying top level athletes, both in terms of understanding a leak performance and also translating such knowledge to amateur and recreational cyclists. One take away message is that high carbohydrate diets are vital to sustain performance over a prolonged period of heavy training or racing. Another important issue is that are typical Western diet carries more than enough protein even when taking on heavy exercise. Finally, periodic tracking of our own energy intake, especially with the prevalence of nutrition tracking technology available now, may be a useful way of understanding our own energy balance and identifying any potential deficiencies.

Ride strong and have fun!

References
Rehrer N.J., Hellemans I.J., Rolleston A.K., Rush E., and Miller B.F. 2010. Energy intake and expenditure during a 6-day cycling stage race. Scand. J. Med. Sci. Sports. 20: 609-618.

Saris W.H., van Erp-Baart M.A., Brouns F., Westerterp K.R., and ten Hoor F. 1989. Study on food intake and energy expenditure during extreme sustained exercise: The tour de france. Int. J. Sports. Med. 10 Suppl 1: S26-S31.

Sánchez-Muñoz C., Zabala M., and Muros J.J. 2016. Nutritional intake and anthropometric changes of professional road cyclists during a 4-day competition. Scand. J. Med. Sci. Sports. 26: 802-808.




About Stephen:
Stephen Cheung is a Canada Research Chair at Brock University, and has published over 90 scientific articles and book chapters dealing with the effects of thermal and hypoxic stress on human physiology and performance. Stephen’s Cutting-Edge Cycling, a book on the science of cycling, came out April 2012, and he is currently co-editing a followup book “Cycling Science” with Dr. Mikel Zabala from the Movistar Pro Cycling Team. Stephen can be reached for comments at stephen@pezcyclingnews.com .

 

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