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Cycling nutrition: Your ultimate guide

Cycling Nutrition
(Image credit: Getty Images)

Most cyclists who race will put themselves through hell in training to add 10 watts to their FTP or 200 watts to their sprint. Many of them will happily spend vast sums of money on the best aero road bikes, deep-section wheels, power meters and tight-fitting skinsuits. But very few of them will give proper attention to their diets, often following lazy or outdated advice which has been passed down from previous generations. But don’t worry, we’re here to give you a brief but comprehensive guide as to what you should be eating on and off the bike to help you adapt to training and perform at your peak on race days. 

It’s important to note that cycling to get faster in races and cycling to lose weight are two different things. The same is true for nutrition, and whilst some of the advice in this article might be useful to those wanting to lose weight, this article is mainly focused on the racing cyclists out there.

Fuelling

Racing road bikes isn’t a simple one-size-fits-all type of sport, so you shouldn’t plan your nutrition as though it is. The most commonly raced events are road races, criteriums (or crits), and cyclo-cross, although the emergence of gravel racing is a welcomed addition. The demands of gravel racing are similar to those of similar duration road races, so we’ve grouped the two of those under the road racing banner, likewise crits with cyclo-cross events. 

While you might be tempted to use any new advice in your next race, you really shouldn’t. All athletes are different and whilst general guidelines can be given, you never know how you’ll react to new practices. The best thing to do is to plan your race-day nutrition and give it a couple of trial runs on a tough group ride or the local chain gang to see how you react. That way, if anything might not go to plan you can change things before your race, and you won’t end up doing a Dumoulin.  

Road races

There are two main macronutrients that the body will use for creating energy during exercise: carbohydrate and fat. Carbohydrates are the sugars, starches and fibres found in fruit, grains and vegetables. Once they’re ingested, we can use them for energy, to maintain blood sugar levels, or to replenish liver and muscle glycogen stores. Fat is found in some plants and most animals, and is something that we store in abundance; even the leanest of riders will have several kilograms of it on their bodies. It is also much more calorific than carbohydrate, with nine calories in a gram of fat compared to just four calories in a gram of carbohydrate.

We know this is bound to annoy some low-carb, high-fat, ketogenic diet fans, but we must make this clear from the outset: when it comes to road racing performance, carbohydrate is king. On balance, fuelling properly with carbohydrate is the single biggest enhancer of performance on a bike. Ketogenic diets do have a place in low intensity, ultra-endurance events, where fat can become your primary fuel source, but in WorldTour and amateur road racing, carbohydrate is by far the most important fuel source. In anticipation of some likely comments; yes Chris Froome once ate a low-carb breakfast, but he did not win the Tour by going ketogenic. To our knowledge, no Tour de France, Giro, Vuelta, world championships or Olympic road race has ever been won by an athlete following a ketogenic diet. 

So why are carbohydrates so important? 

As you exercise at high intensities, you’ll use mainly carbohydrate that is in your liver, blood and muscle. The feeling of fatigue that develops during long road races is linked to low blood sugar, liver glycogen and muscle glycogen levels, and it is because of this that will have heard the advice to carb load in the days before racing. If your race is longer than 90 minutes then you should be eating plenty of carbohydrates on the day before the race. Anywhere between six and 12 grams of carbohydrate for each kilogram of your body weight, depending on the length of your race.

On race day itself, once again, carbohydrate is the key to performance. There have been concerns that eating carbohydrates in the hour before exercise could lead to reactive hypoglycaemia (low blood sugar). However, there seems to be little evidence that this has any negative effects on performance, so we recommend ingesting 20-30 grams of carbohydrate about 15 minutes before the start of a race. The amount that you eat during a race depends on the length of it, but the following recommendations should be used:

  • A race of 1-2 hours: 30 grams per hour
  • 2-3 hours: 60 grams per hour
  • 3 or more hours: 90 grams per hour

The limiting factor for how much of your ingested carbohydrate you can use during a race is the rate at which your gut absorbs it, and this is where multiple transporters might come in handy. Glucose and fructose, two of the most common sugars seen in sports nutrition products, are absorbed by different transporter, so we often see products with the two combined. Glucose can be absorbed at a rate of 60 grams per hour, and fructose at about 30 grams per hour. So, if you’re aiming to eat 90 grams of carbohydrate per hour, you should try and get 60 grams from glucose and 30 grams from fructose. However, it’s important to note that glucose is absorbed quicker than fructose, so if you’re only aiming to eat 60 grams per hour, you should make sure it’s all glucose or maltodextrin.

Crits

During longer road races, the benefits of carbohydrate ingestion are mainly metabolic, such as keeping muscle glycogen levels topped up. While we don’t need to worry about that in crits, there are still benefits to ingesting carbohydrate, even though we don’t have time to fully absorb what is eaten. Rather than the advantages being metabolic, the benefits come about by effects on your central nervous system. While it is not completely understood, we know there are receptors in your mouth that can sense carbohydrate, and this can be linked to improvements in performance. So in your next crit, don’t be afraid to take a gel for the last 15 minutes or swig little and often from a carbohydrate drink. 

Training

The aims of a race and a training session are completely different, and you should treat your nutrition as such. The aims of your training can also differ hugely, whether it’s improving your five-minute power, FTP, sprint or ability to ride for long durations. 

If the aim of your session is to ride hard, then you need carbohydrate to fuel it. When you perform high-intensity efforts you’ll use almost exclusively carbohydrates, so if you’re low on carbohydrate, you won’t be able to hit the number you want to. Treat these high-intensity sessions similarly to how you would a race; if you’re going to be out for five hours and doing plenty of efforts, eat plenty of carbs.

However, there are times where you might not want to eat carbohydrates during your ride, or you might even want to start your ride glycogen depleted. The benefits to these low carb rides are twofold. Firstly, they can teach your body to become more efficient at using fat as a fuel source, meaning you will learn to 'spare' muscle glycogen for when you need it in races, like the high-intensity efforts that can win you races. Secondly, it could help you adapt more to exercise. One of the main ways we adapt to repeated training sessions is by increasing the number of mitochondria in our muscles and completing training sessions with low muscle glycogen levels has been shown to increase the rate at which we create new mitochondria. 

There are several ways to train with low carbohydrate, and these include

  1. Doing two sessions in a day with minimal refuelling between sessions
  2. Consuming a low carbohydrate meal the night before a ride
  3. Skipping breakfast before a ride
  4. Have a normal breakfast, but avoid eating carbohydrate during the ride itself.

It is common to find that your power output is lower than normal when training low carb, but some of this loss can be restored by using a carbohydrate mouth-rinse. Just swill a carbohydrate drink in your mouth for 10 seconds every five minutes and spit it out... just watch out for your fellow riders. 

One of the big issues with riding low carb is bonking. This happens when we’ve depleted most of our muscle glycogen, and the levels of sugar in our liver and bloodstream are getting low. It’s the feeling of fatigue and hunger, and it’s horrible. One way to avoid this is to take some high carbohydrate food out with you as a backup. If you’re still miles from home and you feel the hunger knock coming, don’t be afraid to eat the carbohydrates to help you get home - the negatives of digging a hole that takes three days to recover from will fast outweigh the benefits gained from training low carb in the first place. 

Another huge caveat with low-carb training is that doing it too often can ruin your ability to perform the high-intensity efforts that are key to doing well in races. There are several important enzymes in your muscles that allow you to produce energy quickly enough to perform high-intensity efforts, and chronically training without carbohydrate can reduce the amount of them in your muscle. In light of that, we suggest that you periodise your nutrition in the same manner that you periodise your training. You may wish to avoid carbohydrates in some easier days, but on those tough days, make sure you fuel properly.

Hydration

During exercise, your body produces a lot more metabolic heat than it normally does, and the main way of losing this excess heat is sweating. If you lose more than three per cent of your body mass in sweat (2.25kg for a 75kg rider), it will most likely have significant detrimental effects on your performance.

Pre-exercise, you should aim to drink about 500ml of fluid about four hours before starting. The next time you urinate, if it is dark in colour, you should aim to drink the same amount again, and keep doing so until your urine is light or clear in colour. Some people sweat so much during exercise that they might struggle to replace all the fluids that are lost, and they may benefit from hyperhydrating before exercise. While there are potential benefits, it does increase the risk that you may have to stop to urinate during the race, so be careful.

If you consume more fluid than you lose through sweat, there is a risk of developing hyponatraemia; where the sodium in your blood becomes diluted. The symptoms of this include confusion, weakness and fainting. In the most extreme cases, seizures and even death have occurred.

The best way to find out how much fluid you should ingest is to weigh yourself pre- and post-ride in various weather conditions and keep notes. If you’re finishing rides several kilograms lighter than when you start, you’ll know that you should be drinking more in future. It’s best to experiment a bit until you’re finishing rides no more than two kilograms light than when you started.

Post-ride

The first thing that’ll go through many minds here is protein, but why? Protein, or the amino acids that make it up, are the building blocks of all the cells in the body, including skeletal muscle. The theory goes that if you eat protein, it’ll be converted into muscle, which is why a lot of athletes grab a protein shake the second they’re finished working out. However, this shouldn’t be a huge concern to most cyclists. Whilst supplemental protein can help increase protein synthesis rates following weight-training, there is little evidence to suggest that it has any beneficial effect on endurance performance. If you’re consuming 3,000 to 4,000 calories a day to fuel your training, then you’re most likely consuming more than enough protein anyway without having to use supplements, and we’d always recommend consuming whole foods over supplements where possible.

What should be of more concern for endurance athletes is refuelling with carbohydrate after races or tough training sessions. If you’ve completed a hard ride and need to do the same again the day after, you should begin replenishing your glycogen stores as soon as your ride is finished.

Supplementing with caffeine

Caffeine is arguably the most commonly used supplement in sport due to its performance-enhancing effects. Don’t be tempted to think that higher doses are better as you couldn’t be further from the truth. The main effect of caffeine is through the central nervous system, and you need only 200 milligrams to experience these effects. Much higher doses have been linked to stomach cramps, gastrointestinal distress, and unsurprisingly, decreased performance. Some people worry that regularly consuming caffeine before and during training rides might lessen the beneficial effects on race day, however, there is no evidence to suggest habitual use reduces its effectiveness on race days.

Supplementing with Beta-alanine

This supplement comes into its own during very high-intensity efforts. During these efforts, which typically last from two to five minutes, your muscles become acidic which reduces the ability of your muscle to contract, and your power output decreases. As a side note, this is not caused by lactate. Don’t listen to anyone who tells you the burning in your muscle is lactate. It is, in fact, the accumulation of hydrogen ions from other processes, and lactate helps our muscle deal with clearing these ions. 

Taking beta-alanine over an extended period prior to race day (think weeks and months) increases the amount of carnosine in the muscles, and this can help counteract the increase in acidity in the muscle, helping you perform high-intensity efforts for longer. Whilst there’s no evidence to suggest beta-alanine will harm your performance in road races, it’s effects should be particularly useful in crits where you’re repeatedly performing high-intensity efforts. Regardless of your body weight, for the first 4 weeks, you should ingest about 3.2 grams per day, and 1.6 grams per day following that.

Conclusions

While the most important nutrition message is that you should fuel appropriately to your aims, this perhaps isn’t the single most important piece of advice. That is that you should experiment with and optimise your nutrition practices during your training sessions, so when it gets to race days, poor nutrition isn’t going to undo the months of hard work you've put in on the bike.