Not as fun as it sounds, bonking on your bike can spell disaster for any ride or race, but it's easily prevented with good natural nutrition and a well-practiced fuelling strategy. 

What is a cycling bonk?

Bonking, or blowing-up, is the cycling term for what runners might call ‘hitting the wall’. Essentially it's when your body runs out of energy during a bike ride.

Once you've blown-up you feel absolutely terrible, as if you simply cannot go on. When your energy levels have dropped this low it is very hard to recover and continue.

It can happen to a cyclist of any level or experience, even professional racers, if they do not manage their energy intake properly. There are many reasons this happens... the weather, distractions, ignorance, focussing on keeping up rather than your own limits, carrying foods you dislike (such as gels etc), and many others.

If you are taking part in long rides of over 90-minutes then learning about the dreaded bonk, and more importantly how to prevent it, will make sure it doesn’t happen to you!

What are the symptoms of bonking?

When you bonk, or blow-up, the change can be sudden; your legs feel weak, you lose your focus, your heart rate increases and you may feel dizzy, woozy and confused. From feeling strong you will suddenly feel like you are cycling through treacle. It's horrible.

In a race or cycling event it essentially spells ‘game over’ as eating and drinking at this late stage will not be enough to help you return to previous effort levels, all you will be able to do is limp to the finish.

If you've let yourself become dehydrated too, then you're potentially in real trouble and need to get yourself sorted, fast.

Marc Giusti, founder of Veloforte, has his own story of blowing-up on a ride, and how it sent him in search of more natural energy foods:

He was trying to get back to form after an operation but couldn’t find anything he was happy to eat on the bike, so wasn’t progressing very fast. He was putting bananas in his back pocket but found that the pace and distances he was riding meant he'd quickly run out of juice.

"There is a route I frequently do from my home to Box Hill and back, it's about 100km with around 2,600ft of climbing. Most days I'd stop off at the café at the top, have a drink and a bite to eat, but this time I just zoomed up there and back without the stop.”

Giusti describes the feelings and symptoms,

“I noticed I was knocking my front wheel against pot holes much more regularly, and starting to feel very irritable.  Cars seemed to be passing me closer than usual and the noise of motorbikes would somehow make me angry. Eventually I struggled to keep myself in a straight line. I was ignoring all the signs. Very stupid!”

In the early stages of blowing-up you have a slim chance to bring yourself back, eating something sugary, full of fast-energy now may have helped Giusti dig himself out of the hole, but he continued to ride on.

“As it got worse I started to get this draining feeling in my face, as if the blood wasn’t there, my muscles across my legs were twanging and my vision was blurring in one eye.” 

These are very extreme symptoms and by this point Giusti was well beyond the point of no return, as he recognises now,

“When you aren’t thinking about fuelling for the road ahead that's where it goes wrong. If you are not thinking about what is coming next, preparing for half an hour hence, the mistake has already been made. The return to form after that point is almost impossible. Fuel for the road ahead, not the road you're on!”

Returning home Giusti was in a terrible state,

“I felt horrendous when I got back, I was lying on the kitchen floor with massive cramps, vomiting into a bowl and shaking all over the place.”

Thankfully his wife Lara was on hand with some orange juice and plenty of experience to bring him around,

“She gave me one of those looks that said ‘you've been pretty stupid, you need to sort yourself out!”

Giusti describes the experience now as a valuable one,

“It’s a bit like being drunk for first time. Sometimes you need to experience things to know what it is and how far you can go before you get ill. 

Saying that, it isn’t an experience to be recommended! But still, this story has a fantastic ending, it made me angry that I couldn’t find the natural foods I wanted to eat to be able to avoid feeling like this when I rode. It drove me toward finding a solution, and that solution turned out to be Veloforte.” 

Step 1: Stock up on carbs before your ride

The great news is that bonking is preventable. How you eat before and during your ride is key to this. If you're planning a long ride the first stage is to ensure your body’s stores of energy are full before you start.

Your body stores its energy as glycogen in your liver and in your muscles, this is then released as glucose into your blood stream as you need it.

Eating plenty of carbohydrate the day before your ride is important. Traditionally cyclists loved a pasta party but there are other better sources and the danger of cramming in carbs is that you over eat, then struggle with digestion.

Many cyclists feel that too much carbohydrate can lead to their legs feeling heavy the next morning. Instead eat carbohydrate meals and snacks throughout the day, or two days, before a long ride.

Keep an eye on your total carbohydrate intake, you should be aiming for 6-10g of carbohydrate per kilogram of body weight per day. 

This is just a guide, your level of fitness, your level of excersice and the nature of the food you eat all plays a part. Best thing to do is try and learn what you like. Some eat more, some eat less.

If you don’t want to calculate the maths simply make sure that you have some carbohydrate with every meal or snack, don’t let yourself feel too hungry but don’t leave the table feeling stuffed. Good sources of carbohydrate include sweet potatoes, rice, fresh fruit, vegetables, cereals, dried fruit and oats.

The supply of energy from glycogen stores in your body is however limited to just 90 minutes, less if you're riding very hard, therefore it is important to keep topping up throughout your ride.

Step 2: Maintain glycogen levels with carbs during the ride

If you are riding hard for more than 90 minutes you will need to top up your body’s reserves by taking on carbohydrate throughout your ride. You can do this in many forms; drinks, energy bars, natural food, or a combination of these.

You should be aiming for 60-90g of carbohydrate an hour. If you are using foods, such as dried fruit or natural energy bars, that contain a source of fructose (the sugar from fruit) as well as glucose then the energy provided can be absorbed even more quickly that just one of those carb sources can alone.

Over eating can lead to its own problems of gastric distress; bloating, cramps and slow digestion, so make sure you have a good handle on how much you are eating.

Eating little and often is the best way to keep your blood sugar levels constant and keep the bonk at bay. Aim to eat a little every 20-30 minutes of your ride, starting after the first 20 minutes. Organise your back pockets with bite-size chunks of food that you can easily grab, even if the going is tough, to top up your glycogen stores.

Step 3: Pace yourself

Pacing plays a critical part in preventing the bonk; the harder you ride the quicker you deplete your glycogen stores. Having a plan for a long ride and an awareness of your effort levels is incredibly helpful. This could mean using a heart rate or power meter, if you know your zones, or as simple a strategy of monitoring your breathing and ability to talk. On long rides you should be able to speak brief, short sentences. If you are gasping out one word at a time you're probably riding too hard to last the distance.

Keep an eye on your food intake, a classic scenario that leads to bonking is that the pace heats up and your effort level increases which means you stop focusing on your cycling nutrition strategy as you struggle to maintain the effort. You are using more fuel than you are replacing, which means you are heading into a bonk it will be hard to come back from.

Step 4: Fuel the right way with natural energy bars

Natural cycling energy bars and whole foods are a great way of making sure your body has the fuel it needs in an easily digestible and enjoyable format. You cannot under estimate how important it is to have food that tastes and smells good, so that you look forward to those bite size moments of energy intake. If you don’t like the taste it is much harder to force yourself to eat, fuelling becomes a chore, not a source of motivation.

Your digestion starts with your eyes and your nose, when your mouth waters the saliva begins the breakdown of food into useable energy. Amazingly your body starts to release more glucose into your blood stream as soon as it tastes it in your mouth, even before it hits your stomach. Natural energy bars, such as Veloforte, taste wholesome and delicious triggering all of your digestive system so the energy reaches your muscles as soon as possible.

Real, natural food and energy bars contain more moisture and fibre than manufactured products, water is really important for digestion and energy release. Very dry food is hard to chew and swallow, especially when you are exercising hard, and even more difficult for your stomach and gut to breakdown into fuel.

Natural bars, such as Veloforte, are stuffed full of tasty dried fruits, a great source of the natural fruit sugar fructose, which in combination with glucose (from honey or cane sugar) increases the amount of fuel your body can absorb per hour. The more fuel your body can absorb and use, the longer you can ride.

 “What should I do if I find myself bonking whilst cycling?”

If you feel the tell-tale signs of a bonk on the way, it can be headed off if you act fast and haven’t already dug too deep into your reserves. Begin fuelling again immediately but keep to your strategy.

Shovelling down too much food in one go will only slow down your digestion and over load your stomach and gut.

Have a look through your pockets for the foods that release energy fast and start with them; dried fruit, a very ripe banana, a Veloforte bar, or a couple of swigs of an energy drink for example. If you have also neglected drinking you could be in a serious situation. 

Make sure you are well hydrated as you need water to digest the food you are putting in and to look after your whole system. Ease off the pace to reduce the strain on your body and allow it to digest.

Right now the key things to focus on are recovering your energy levels and not heading any deeper into a pit of negative energy balance.

As you start to feel better pick up the pace again. You may already have lost the chance of a PB or a good race finish but with care and a return to your good fuelling strategy you can still reach the end of the ride in good shape.

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