Nutrition For The Tour De France Femmes

This week, we’ve seen the third edition of Tour De France Femmes get underway in Rotterdam for the third edition of this exciting flagship race for women's cycling. 

Much like the Tour de France, completing the TDF Femmes is an extreme feat of human endurance, up there as one of the world’s most extreme endurance events. Although the race is over eight days with zero rest days compared to the men's 21-day race with three rest days, it covers close to 1000 kilometres. The demands of individual stages are comparable to those within the men's race, with even double race days thrown into the mix.  

As your resident sports nutrition enthusiasts, we explore what it takes to fuel the Tour De Frances Femmes in this week's blog. 

Whilst there is generally a significant lack of published research in female athlete nutrition (less than 5% of sports science research includes female subjects), and the Tour de France Femmes is only three years old, an academic from Liverpool John Moores University led a team that followed Australian professional rider and all-rounder Georgie Howe of the Liv AlUla Jayco Professional Cycling team through the 2023 edition of the race. Through a published case study, it provides some groundbreaking (this is likely the first scientific insight we have into a woman’s grand tour) insight into the nutrition demands of the race.

Before the race, Georgie visited a physiology lab, where her resting metabolic rate (the energy she requires at rest), body composition (using a DEXA scanner), and fitness were assessed with a maximal exercise test. This helped ensure the accuracy of the race energy expenditure data and examine aspects like bone mineral density and body composition.

During the race, they then tracked Georgie’s total daily energy expenditure using a highly accurate and expensive technique (costing thousands of pounds per person) using doubly labelled water and her exercise energy expenditure using the power output data from her power cranks. They also tracked her dietary intake, weighing out food using scales where possible in combination with a photographic food diary. This produced some fascinating insight using some of the best techniques available into the nutritional demands of this extreme endurance event and how Georgie fuelled it.

How much energy did she burn? As we can see on the graph below from the study, on average, Georgie was expending just over 7500 kcal per day—equivalent to over four times her normal resting energy requirements! This is towards the reported limits of human endurance and quite similar to what we see in the men's Tour de France. Individual stages expended between 600kcal (for a short time trial) and 4300kcal (on a big day) to fuel the stage alone, so it's safe to say vast amounts of energy were expended on the bike during the race! It's also likely to be one of the highest ever recorded energy expenditures (using the gold standard doubly labelled water technique) for a female athlete.

How did she fuel the race? - One of the most interesting insights from the study was that despite taking in, on average, a pretty significant 5246 kcals per day, which would have equated to a lot of food, Georgie still didn't eat enough to match her energy intake to her expenditure. As a nutritionist, one of the critical aspects of diet we'd focus on to ensure a rider could maintain their health and performance during a grand tour is to match their energy intake to their expenditure during a race, so this is a pretty significant finding. In theory, you’d expect a rider who wasn’t able to fuel optimally to have a reduced performance.  

This 31% energy deficit meant that over the course of the race, she was under-fuelling, on average, by quite a sizeable 2326 kcals per day. This resulted in a 2.2kg weight loss over the course of the 8-day race (that couldn’t be explained by changes in hydration/fibre intake) and showed that Georgia was in a state of low energy availability for much of the race. This was despite taking in between 68-105 grams of carbohydrates per hour on the bike and consuming on average 13.7 grams of carbohydrate per kilogram body weight per day/kg (range 9.7–15.9 g/kg) in carbohydrate alone. On the highest day, this was equivalent to over 1.1 kilograms of carbohydrate! 

This under-fuelling could have resulted from a whole host of different factors, from challenges in consuming sufficient food to possibly a lack of professional support from nutritionists during the race, meaning she may not have been aware of how much she needed to consume in order to maintain energy balance. This under fuelling was inadvertent, with Georgie not intentionally trying to under fuel. The study did highlight a high fibre intake on a couple of days likely lead to increased feelings of fullness and potentially making eating enough a challenge. 

Would this under-fuelling have negatively impacted her performance? We don't know, as a case study like this doesn't allow us to accurately see if she would have performed better had she consumed more food. We also have a number of studies showing that short term weight loss in controlled training situations can also negatively impact performance. Of note was that she was also able to produce a performance that was in line with that of other world tour riders, and she even produced a personal best performance on the race's last stage. Which could suggest she was still able to perform well despite under-fuelling.  

It's important to note that one of the critical implications of low energy availability (as a result of under-fuelling) in female athletes is irregularities in the menstrual cycle, which, in the long term, can lead to poor bone health. When she was screened in the lab prior to the race, she reported some menstrual dysfunction, and the results of the DEXA scan showed she had low bone density in her lower spine and head of femur which would suggest she was under fuelling prior to the start of the race.

Alongside her total intake of energy and carbohydrates, they also reviewed her fat and protein intake. Sports nutrition guidelines typically don't recommend protein intakes much above 2.2 grams of protein per kilogram body weight, but in line with what we see from male riders in a grand tour, protein intakes in this study were also very high, around the 2.1-3.1 grams per kilogram, often owing to the high intakes of food and the protein content of foods like bread and pasta. Fat was also similar to what we'd see in male grand tour cyclists, typically around the 1-2 grams per kilogram body weight per day. 

From this case study, it is clear that the Tour De France Femmes is an incredible feat of endurance, and nutrition plays a key role in supporting the rider throughout the tour. If you want to learn more about how to fuel your competition and performance, then check out Fuel The Ride Academy. 

Ben