How many carbs do you need during racing?
In the last article you learned about how many grams of carbohydrate our body - in general - can use during exercise.
This article will be about the generally recommended carbohydrate intake prior, during and after exercise/race. Importantly, it is assumed that the primary goal during the event is to keep exercise intensity high.
Prior the race (days)
Purpose: Supercompensation of glycogen stores
Supercompensation of muscle glycogen stores is a popular strategy among many endurance athletes. The idea is that consuming high (higher than normal) amount of carbohydrate some days before the race will result in a supercompensation muscle glycogen stores in the muscles (∼500g) and the liver (∼100g) (all together around 2000-2400kcal). The idea behind supercompensation is to increase glycogen storage above physiological levels to lengthen the duration of carbohydrate availability to exercising muscles, thus improve performance.
There are three different protocols:
1) The classic glycogen loading protocol is (longer version): 3 days of hard training on a low-carb diet (<5 g/kg body weight/day) followed by 3 days of tapered training on a high-carb diet (8-12 grams of carbohydrates per kilogram of body weight)
2) “Modified glycogen loading: 3-days taper on a high-carb diet with 24-h rest prior to competitions”
3) “Short version” (duration of 1-3 days): A high carbohydrate diet (8-12gram of carbohydrate /kg body weight) with appropriate rest.
Prior the race (hours)
Purpose: increase resting levels of glycogen in the muscle and liver
Try to eat an easy-to-digest high carbohydrate meal 2-4 hours before exercise. General guidelines suggest to consume carbohydrate in quantities ranging from 1 to 4 gram/kg/ bodyweight.
During the event: event is shorter than 1 hour:
In normal conditions, if we start the race with fully replenished glycogen stores, the body should sustain high intensity output for like 60-90 min. Interestingly, mouth rinsing with a carbohydrate solution as a pre-race technique showed to improve cycling performance during a 1h time trial. However, in case you start the race on low carbohydrate availability, it is suggested to take some carbs during the race (15-30g of carbohydrate). But again, if the race is under an hour and you had high carbohydrate containing meals before the race, probably you don’t need to ingest anything.
Event is between 1 hour and 2.5 hours
Here we start to consume exogenous carbohydrates. Which products (gel, bar, drink) you use is up to your preference, availability, needs etc. To note: As we start exercising blood flow to our muscles increases but in the same time less blood will go to other parts of the body, for example to the GI tract. Riders might feel either a decrease and/or change in appetite. Also, during high intensity races, riders might have limited opportunities (lack of time or availability) to consume energy, therefore it is recommended to eat easy to consume and digest products such as gels over bars.
Studies suggest to keep carbohydrate intake between 30-60g/hour. Recommended types of carbohydrates are glucose, glucose polymers, glucose-fructose (including sucrose).
Event is longer than 2.5 hours
The recommended intake is between 60 up to 90 g/hour. In this case, we definitely need to consume multiple transportable carbohydrates in order to maximize absorption and avoid GI issues (2:1 ratio of glucose: fructose). We also highly recommend to “train your gut” before trying to ingest this high amount of carbs.
Eating after an event
How and what the rider eats in-between two events highly depends on many factors: in which training phase we are, goal of the next training session, rest period between the sessions etc.
In case we have at least 24 hours or more between trainings then actually following a normal, healthy and balanced diet should be good enough to replenish glycogen stores. Long term glycogen recovery is mainly affected by the total amount of carbohydrate ingested and less by timing.
However, if we have 24 hours or less (like a multistage event), then we definitely need to focus on what to eat and when. Again, we assume that the intensity of the next training session is high, therefore we want to make sure that our glycogen stores are fully replenished. After training, the muscles are more sensitive to take up glucose and synthesize glycogen. It is suggested to take 1.0-1.2g/bodyweight/hour of carbohydrate in the first 3-4 hours. High carbohydrate consumption is crucial which can be achieved only through diet but riders can also use supplement such as sports drinks/shakes. Consumption of high glycemic index foods (rice, white bread, potatoes, sugar and sugary drinks, bananas, grapes, raisins and dates) are advised as these products can speed up muscle glycogen replenishment .
General suggestion for a 70kg person:
Days before the race 1-3days:
- Around 560-840g carbs per day
Race day:
- Pre-race: 2-4 hours before the race around 70-280g carbs
- Race (4 hours): 240-360g carb total
Post race
- First 4 hours: 280-300g carbs total