Optimizing Endurance Cycling Performance with Intermittent Fasting and Cycling

Author: Rhys

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In recent years intermittent fasting and cycling has become profoundly popular as a method to – according to its proponents – lose weight and regain health.

The concept of only eating within a short period of time each day is an odd idea to many, and to an endurance cyclist seems almost impossible. 

But what if you’re one of these heavier riders that struggles to lose the extra pounds that hold you back while climbing, and make your jersey just a little too tight? Can IF help you or is it just another dieting craze that deserves no attention? Let’s take a closer look.

Plate with food and alarm clock on yellow background, interval fasting concept

Understanding the basics of intermittent fasting

Intermittent fasting (‘IF’) is simply the notion of adjusting your eating patterns such that you only eat within a certain time window each day, thus avoiding constant snacking and eating habits that may lead to overconsumption. 

The most popular method for beginners is to eat within an eight-hour window each day. As an example, begin eating your first meal at 1pm and finish your final meal by 9pm on that same day.

No breakfast or snacks beforehand and no treats afterwards, strictly fasting until your window opens, and stopping when it closes.

While an eight-hour eating window is popular, some more advanced fasters may even decrease to a six or four-hour eating window in order to accommodate their lifestyle and goals.

By restricting food intake times, the body adapts and begins to more quickly and efficiently utilize fat stores for energy. In other words, you’re training your body to burn fat, not store it.

For cyclists seeking to lose that extra weight, this might just be the key to complementing their on-bike efforts.

intermittent fasting and cycling

The Pros and Cons of Intermittent Fasting for Cyclists

Why intermittent fasting works

Unlike most diet changes and trends, intermittent fasting (‘IF’) is considered a long-term sustainable nutrition strategy that is particularly suitable for people that have a tendency to overindulge.

The eating window can be adjusted according to your biking schedule as well as your unique lifestyle and situation – and it’s not unnecessarily restrictive. 

Various freshly squeezed vegetable juices for Fasting

Want to have a beer while watching Paris-Roubaix? You can work that into your daily IF plan. Want to celebrate your daughter’s birthday with some cake? Again, an IF lifestyle can accommodate that desire.

Aside from being a long-term strategy, the results of an IF lifestyle come surprisingly quickly:

  • Within one week you will notice how alert and confident you have become, and that your sleep is more enjoyable.
  • Within four weeks you will notice some significant weight loss on the scales.
  • Within eight weeks you will notice your body structure starting to change – the face is less round, the belly is becoming flatter and the legs are looking more like, well, cyclists’ legs.
  • Within twelve weeks other people (your friends and family) will start to notice these changes in you too and you may even start to receive some comments (‘have you lost weight?’). At about this time, you might be noticing how loose your cycling kit has become. 

Each of these factors adds to the motivational snowball to keep going to accomplish what it was that you set out to achieve. Meanwhile, your power-to-weight ratio is rapidly increasing and you’re setting Strava PR’s left, right, and center.

When intermittent fasting won’t work

Like most training habits, intermittent fasting (‘IF’) works great when it is done on a repeated and regular basis. However, if it is done ad hoc the consequences can be quite negative.
This study published in the European Journal of Sport Science [1] found for a cyclist that is not on the IF regimen, that omitting a carbohydrate-rich breakfast will impair evening endurance exercise performance.

What a cyclist can expect with intermittent fasting

The first few days are difficult. Your body clock is telling you you’re hungry and that feeling is hard to resist. The best way to get through this is to keep yourself busy during the hunger pains and your body will ‘forget’ that you were hungry in the first place.

(This is because your body is responding to the habits developed over your lifetime. At a certain time of day, your body clock will remind your brain that it’s time to eat, therefore making you feel hungry.)

Pretty quickly, you’ll notice how alert and aware you are. A common misconception is that IF will make you drowsy but in fact, the opposite is true – energy you never knew possible comes out and as each day goes by you find yourself more willing to ride hard during a training session, more willing to keep up with that group on Zwift and even more willing to do the house chores. 

3 riders on zwift performing a workout

Long-term, the results can be extraordinary. A leaner body structure means you’ll be able to hold a greater power-to-weight ratio, perfect for climbing. Additionally, clothes that were tight fitting become looser.

All the while costing you less money (less food to buy) and taking less time away from your busy lives (less food preparation).

Effects on Performance of Intermittent Fasting for Cyclists?

Putting all those factors together, an average biker should become a faster cyclist in a relatively short period (months, rather than years) thanks to an intermittent fasting schedule.

When should a cyclist consider an intermittent fasting regimen?

The easiest time to begin with intermittent fasting is during a low-volume biking phase. Perhaps early in the season or during a planned mid-summer break. This allows the body to adjust to new eating habits without the worry and in some instances the burden, of riding the miles.

If you feel good, this can then carry over to periods of higher volume riding, when you’re clocking up the miles. Of course, don’t be afraid to adjust your fasting schedule to accommodate your riding.

Is intermittent fasting the death of carbohydrate loading?

For decades endurance athletes have been advised to ‘carb load’ before an important event. With the above revelations, does intermittent fasting (‘IF’) mean we no longer need to carb up? Well, not exactly.

If you’re enjoying the benefits of an IF lifestyle then you can focus on eating some quality carbohydrates in the few days immediately prior to an important event. Indeed, carb-loading and IF can easily work together and help you avoid overdoing it. 

For many amateur athletes, the idea of carbohydrate loading meant overeating prior to an event. With IF, this will help you keep that notion under control.

carb loading for cycling training

What are the Risks of Intermittent fasting

Bikers, by their nature, tend to be quite lean. If you’re doing a lot of biking and an honest look at yourself in the mirror you can see some body jiggling where there shouldn’t be, intermittent fasting (‘IF’) might be the right solution for you.

If, however, you look in the mirror and see a lean ‘skin and bones’ figure looking back at you, IF may not be for you – tread carefully on this one. IF will make you lose weight and if you don’t have extra weight to lose, it can be a slippery slope to poor health and of course biking performance.

Keep in mind also that while IF allows your body to burn fat, if you’re doing a lot of biking carbohydrates are critical to keeping you going. 

Nothing ventured, nothing gained

Have you tried intermittent fasting yet? Are you already on the bandwagon or are you hesitant? What’s been your experience? Have you become a faster cyclist because of it? Or have I got it all wrong?

Share your experience in the comments below – the Pedallers team would love to hear how it went for you!

Intermittent fasting and cycling FAQs

Should I cycle while fasting?

Cycle while fasting depends on the type of fast you are following and your overall health and fitness level. If you are doing intermittent fasting, which allows non-caloric beverages, then cycling while fasting can be safe and even beneficial, as long as you listen to your body and adjust your intensity and duration of cycling accordingly.

a cyclist stopping for a drink on a bike ride

However, if you are on a prolonged fast that restricts both calories and fluids, it is not recommended to engage in intense physical activity such as cycling as it can deplete your glycogen stores and reduce your energy levels, increasing the risk of injury and compromising your ability to recover from exercise.

It is always advisable to consult with a healthcare provider before starting any new exercise regimen, especially if you have any underlying health conditions or are new to fasting or cycling.

Can you improve endurance while intermittent fasting?

Cyclists may be able to improve their endurance while intermittent fasting, but the extent of the improvement depends on several factors, including the type of fasting regimen, the intensity and duration of exercise, and the individual’s overall health and fitness level.

Some research suggests that intermittent fasting can improve metabolic flexibility and increase the body’s ability to use fat as a fuel source during exercise, which could potentially enhance endurance performance.

However, it is important to note that fasting can also reduce glycogen stores and energy levels, which could have a negative impact on performance if not managed properly. It is essential to listen to your body and adjust your training intensity and duration accordingly.

Can cyclists do intermittent fasting without compromising performance?

Cyclists can potentially do intermittent fasting without compromising their performance, as long as they follow some important considerations.

It is essential to ensure that you are well-hydrated and adequately fueled before and after exercise, and adjust your training intensity and duration accordingly.

It is also important to consider the timing of your fasting and eating windows to ensure that you have enough energy for exercise and recovery – so plan your eating and riding times to complement each other.

It is important to listen to your body and adjust your fasting and exercise regimen based on how you feel and perform. 


  1. Richard S. Metcalfe, Matthew Thomas, Christopher Lamb & Enhad A. Chowdhury (2021) Omission of a carbohydrate-rich breakfast impairs evening endurance exercise performance despite complete dietary compensation at lunch, European Journal of Sport Science, 21:7, 1013-1021, DOI: 10.1080/17461391.2020.1797890
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He often jokes that he was 'born on a bike,' and the pursuit of bike racing took him from his home country of Australia all the way to Europe. With a Bachelor of Applied Science university degree to his name, Rhys is THE expert of all things two wheels.
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