To perform effectively during exercise one of the main fuels a body burns for energy is carbohydrates. Most cyclists have felt the effects of fatigue as a result of the depletion of carbohydrate (or glycogen) in the muscles and liver and, when experienced at a high intensity some can even experience what’s known as ‘the wall’ or ‘bonking’. This is when the tank feels empty and legs have reduced power – essentially you’ve run out of fuel.

In addition to this, to effectively recover and adapt the body in response to the exercise, carbohydrates are also needed to replenish the stores and support muscle development.

Rule #10 states: “It never gets easier, you just go faster”, or when put by Greg Henderson “Training is like fighting with a gorilla. You don’t stop when you’re tired. You stop when the gorilla is tired.”

To counter this bonk effect you can either use a method known as ‘carb loading’ which, through clever methods of carb consumption before exercise, is designed to maximise your bodies storage / fill up the tank; or consume energy as you ride. The type and duration of exercise will determine which technique is most effective and how best they can be combined.


Carb Loading

This technique has a finite effect since the body can only store a maximum amount of carbohydrate: ~400gram, enough to fuel roughly 90 minutes intense cycling. Each person is different and the effects of general nutrition fluctuation, recent exercise, dieting etc. can cause levels to vary massively.

Strategies can be employed to improve your overall storage amount and help target event day readiness, and with carb loading you can increase your body’s stores by 30% or more.

Typical Technique

For 3 days leading up to an event, each morning consume some fast acting carbs like an energy drink. Then after 30 minutes, warm up on the bike for 10 minutes or so before hitting an intensive 3-5 minutes sprint. You should feel the lactic acid build up during this sprint, which will encourage your body to store carbohydrates.

Continue to consume about 10grams of carbs per kg body weight throughout the day. Try to eat more frequently to avoid over eating in single sittings (5/6 meals) and remember it’s about increasing your percentage carbs in your diet rather than consuming more total calories. Supplementing with energy foods can help achieve this without consuming massive amounts of food and can also be more convenient.

You are likely to gain some weight during this period which is primarily down to increased water retention due to carb storage, however don’t worry as you’ll likely burn off all the carbs in your event 🙂


Consuming During

Consider events like sportives which are long and tough. Simple carb loading is unlikely to be enough to fuel you throughout. Taking on energy while cycling in the form of drinks, gels, bars etc can help continue performance to the end.

Research has shown that the majority of people can only absorb up to 60g of carbohydrate per hour as this represents the maximum amount that can cross the intestine walls into the blood stream. Mixing up the type of sugar you consume, for instance products that include fructose, can help raise this limit to nearer 90g as fructose is absorbed via a different mechanism in the intestine. However recommendations from institutes like the GSSI have suggested that most cyclists can achieve greater gains from improving the efficiency of their absorption rather than moving onto combination products. However the benefits are there even though fructose is both slower at absorbing and releasing.

Some loose guidelines to carb intake during event participation:

[-] less than 45 mins – Likely no carbs required.

(Although drinking some carb based drink has shown to have a positive effect even for shorter events due to the ‘mouth rinsing’ effect.)

[-] 45-75 mins – Mouth rinsing.

[-] 1-2 hrs – Up to 30g/hr carb consumed.

[-] 2-3 hrs – Up to 60g/hr carbs consumed.

[-] more than 2.5 hrs – Up to 90g/hr of combination carbs.



Restocking the body’s carbohydrate stores can help muscle and energy reserve recovery as well as the ability to perform strenuous exercise again efficiently. Optimising both carbohydrate and protein intake can support all of this. There is no clear consensus of the best combination of carb to protein for recovery but a useful rule of thumb is something between 2:1 and 4:1 in favour of carbs.

I’ve pulled together a few useful guides:

[-] When rest between exercise periods is under 8 hours you should consume carbohydrates as soon as practical after the first workout to maximize the effective recovery time between sessions. More importantly, in the absence of carb intake, refuelling is ineffective.

[-] When carbohydrate intake is sub-optimal for refuelling, adding protein will enhance glycogen storage.

[-] Early refuelling may enhance a higher rate of carbohydrate intake, especially when consumed in frequent small sittings.

[-] During longer rest periods or 24 hours or more, as long as enough carbohydrate is consumed the type and timing isn’t as important.

[-] Your body has a maximal absorption rate of sugars (roughly 60g/hr) but mixing the sugar type (inc  Fructose for example) a can increase this.

Please check out future it’s a hard cog life blogs for more discussion on recovery.


Carb Unloading

As a technique originally designed to support carb loading the concept is to exercise heavily to deplete stores thereby encouraging it to store more energy than it would normally have done otherwise. Depending how you respond to this technique which can prove exhausting you may prefer just following the process of upping carb percentage in your diet.

However performing some carb unloading style exercise can be very beneficial to training effort.

Training Session Idea (

Something to undertake when you are naturally at low energy levels like first thing in the morning. Perhaps do this type of training on your way to work?

If your cycle commute is typically between 30-60 minutes in duration, riding fasted is an excellent way to develop riding economy, enhance your body’s ability to burn fat as a fuel and facilitate weight maintenance or loss. Do not eat any food before setting off on your ride but you may have some water or a black tea or coffee. It’s essential that the entire ride is in heart rate zones 1-2 (120-150bpm / 60-75% max heart rate ish). With low blood sugar levels you will not be able to sustain any harder efforts and, if you attempt to, you will not get the benefits from the ride and will probably come to a grinding halt. When you first start attempting this session, ride primarily in Zone 1 (~120-130bpm / 60-65% / easy going) but, as your body adapts, try to ride at least 50% of it in Zone 2. Make sure you have some food available to eat immediately when you get to work as you will feel very hungry.


 cassetteA Cog in Time


“The yellow jersey was first introduced to the Tour de France in 1919, as yellow was the colour of paper the French newspaper (formerly L’Auto, now L’Equipe) that sponsored the race was printed on.”






A hub of reviews, advice and news from the online road cycling experts at ProBikeKit.