Beat the Bonk

Borrowed from quoc

If there’s one thing to avoid on the bike, it’s the bonk. Runners hit the wall, cyclists bonk. And as every rider knows, the hollowed out, broken down feeling that comes from flatlining sugar levels is about as welcome as a mid-ride puncture, or the dubious tang of a poorly rinsed bidon.

When it comes to bike nutrition, everybody has an opinion. Also, genetics: your four cups of get-me-up-that-climb coffee could put another rider into the hedgerows. But even when we take our differences into account, surely there are some fundamental nutritional facts that work for everybody?

At The Pedaler, we wanted to understand what we should be eating on the bike, what we shouldn’t, and of course, how to dodge the dreaded bonk. With a little help from our friend Natalie at Trailnuggets, makers of flavourful, healthy bike snacks, we called up Leah Black from Colorado’s Run Wild Nutrition, to talk through sugars, science, and get-me-home gummy bears.

Let’s start with what’s happening when you’re exerting yourself. What’s your body doing and what does it need to sustain an effort?

You hear about carbohydrates as being the main fuel source. But really, it’s all about energy systems and their various stages.

The main source of energy for most cellular processes comes in the form of ATP, a complex, high-energy molecule, informally referred to as the currency of energy. So everything we do, whether it’s breathing, digesting food or cycling, uses ATP. But the problem with ATP is that it’s stored in very small amounts in the body, and so whenever we start exercising, it’s used up very, very quickly – literally within seconds.

When we start doing more prolonged exercise, the body begins a lactic acid-type cycle. This second cycle can get you ATP a lot quicker, but that only lasts for maybe two minutes. So for our conversation, we’re talking about more endurance-based activities, and how we’re going to be getting energy for that, which leads us on to carbohydrates.

Carbohydrates are long strands of molecules, and as we start exercising, they’re broken down into glucose. It is this glucose that our bodies want to use as the primary source of energy to go through the whole metabolic cycle to create ATP.

We naturally store glucose in the form of glycogen in our livers and our muscles, and during exercise, your muscles start releasing glucose from these glycogen stores to be used for energy, which passes into the bloodstream, too. When the liver starts to recognise that your blood-glucose levels are dropping, it begins to shuttle extra glycogen or glucose from both the liver and the muscles into your bloodstream, as well.


So the liver ups the ante. It detects what you’re using, or rather it detects a drop in blood glucose, and it pushes more into the system?

Exactly. So when we talk about a low-carb diet and people trying to do more fat-based diets to let their body run off its fat stores, your body struggles; it’s a more complicated process, and it’s much harder on the body. There’s been no scientific evidence that having a more fat- based diet can improve endurance. Glucose derived from carbohydrates is the main source of energy you need on the bike: your brain runs on it, it goes into your bloodstream, it goes straight to your muscles, and your muscles use that directly for accruing the energy that they need for contractions.

Can some people have naturally more glycogen stored in their body for when they need it or is that diet-based?

I think the biggest thing – and this is why nutrition gets so complicated from the individual to the individual basis – is because it depends on the duration of your activity, how intense it is and how trained you are. But you’re right; the more trained you are, the more glycogen storage you can have.

So as you train and improve, you’re also training your body to be able to store more glucose in the form of glycogen. While it is dependent on a lot of factors, we can say that someone who is untrained and just starting a programme of exercise, is probably going to have lower glycogen stores than someone who’s well-trained.


So when you’re starting out, you’ve got less of an ability to store the energy – does that mean you’re going to need to make sure you’ve got enough bars or gels on the ride because you could be at risk of bonking?

It depends on what your training programme is because I think it is fair to say if you’re starting out, you’re not going to go out and do a five-hour bike ride right away. Well, hopefully not, and if you do, I’d be a little scared for you!

But in general, I’d say if you’re already pretty well in-shape – maybe it’s off-season, and you’re coming back into form – you’re obviously going to start slower.  For a ride that’s for an hour or less, you might not need to carry a bar or a gel to replenish those glycogen stores. But I always say that it’s good to have something just in case your ride goes longer. You could get a flat tyre and need to cope with a banana!

We’ve all been saved by a pocket banana at one time or another.

It’s always good to be over-prepared than under-prepared, but I think regardless of whether you’re trained, or just starting out with a programme, I look more at it from the perspective of the duration of the activity. So if it’s an hour or less I’d say you don’t need to have a whole bidon filled with a carbohydrate-containing beverage full of electrolytes; you might be fine with just water. And you might not even need a bar or a gel. But once again, I’d recommend having something on-hand, just in case.


Sometimes though, keeping things down is hard, and even if you know you need to eat, you can feel a bit sick.

That happened on my first Ironman. Even though I had a nutrition plan, I got on the bike and just felt awful. I had all of this planned nutrition, and then I got on my run, and my stomach was upset, and I just couldn’t eat. However, I’m also a minimalist, so when I go out for a run or bike ride, I’m like, ‘I don’t need anything. I know my limits.’ But now I’m taking a new approach and training my stomach to handle that extra nutrition. When we start adding extra carbohydrates and electrolytes, our bodies and our GI tracts all handle the extra nutritional load differently. If we start off slowly and then increase it based on duration, we can train our guts to handle our nutrition needs much more effectively.


So gradually ramping up your training isn’t just beneficial for your enjoyment of the ride, it’s also better for adapting the body for the extra strain and the extra food you need to be taking on.

Right. And I think the weather is a huge factor, too, because if you happen to be racing on a hot, humid day, you’re losing a lot more, and your body can’t keep up with that extra fuel. You’re going to have a sloshy stomach, and you’re not going to feel good on a long bike ride or run.


And that leads nicely to what you need to eat – is it fruit? Or are you looking for the things like the Trailnuggets products, and if so, what do you want in them as a rough balance and what do you not want in them?

Whenever you’re training, that’s the time to test the foods that you want to consume, and it’s down to personal preference. Some people might want a beverage; they don’t want to carry around foods, because they know it doesn’t make them feel good.

So during training, I think you have to start adapting to what your plan is for race-day, competition or the long ride. That being said, as a general rule of thumb, you should be looking at around 30-60 grams of carbohydrates per hour on your longer endurance events. And for the format, that could look like a gel, a sports beverage, a bar, or it could look like a peanut butter and jelly sandwich!


And it probably will..

Everyone adapts to things differently. My experience in working with other athletes is that when you’re riding, it’s not the time for fibre. Every other time that I talk to people, I’m always encouraging, “Make it whole grains and fruits and vegetables because they’re full of fibre; it’s good for our guts.” But when we’re running and biking and doing these long-endurance-type activities, fibre is going to create bulk in your stomach and make you feel bad. Also, I think fats are another thing that can get people in trouble a little bit. I think it’s a little bit easier on the bike and I do recommend a small amount of fat, just your stomach’s not bouncing as much.

Protein is another interesting area. There’s some research that says consuming protein during exercise can help with recovery. But in general, I don’t think you need high protein content during your workout. The main thing I’m looking for during a race or long training day is easily digestible carbohydrates in whatever form your body prefers.


Because simply, those carbohydrates are going to be turned into the energy that you need?

Exactly. And I think the other thing to note is if you’re doing a bike ride of over three hours, eventually your glycogen stores are going to get depleted, which is why consuming the right amount of carbohydrates can help. But the longer your event goes, the more your body starts adapting to use more fats for energy, but that’s because the glycogen stores have already been depleted. So that’s why we say try to maximise those glycogen stores – once you run out of them, your body’s going to hit fatigue a lot faster, and your muscles might feel more lethargic.


And where does added sugar come into all of this? What is it and why is it so bad?

That’s a great question. When we talk about carbohydrates, there are so many different types. For example, a piece of candy is a carbohydrate, but we would all agree that it’s proper to call it sugar. Whereas if we took a whole wheat piece of bread, we’d say that’s a carbohydrate, yet it will eventually get broken down into sugar. So when we’re looking at something that has added sugar, like the candy in our example, we see neither nutritional value nor nutritional benefit. But when something has naturally occurring sugars, like bread, quinoa or a date-based Trailnuggets bar, you know you’re getting some fibre, anti-oxidants and some extra vitamins and minerals that wouldn’t have otherwise been there.

So even though your energy bar is still going to turn into sugar, it’s just a more wholesome piece of nutrition that has more usage than something that has added sugars for taste and flavour.


And it’s also the speed at which the candy is going to hit your bloodstream that’s the problem?

Exactly. Your blood sugar is going to spike and drop more quickly than if you had something slow-releasing. I use the phrase ‘nutrient density’. When we’re talking about a carbohydrate in the form of a date, fruit or whole grain, there’s so much more nutrient density in those foods, and you won’t get a horrible sugar rush, either!


No more mid-ride flapjacks.

Well, I do think a good example of where added sugar can fit is if you’re about to bonk. If you are really at the point of no return, you don’t want something that’s going to take forever to hit your bloodstream. In desperate need, you want the quickest source of energy available, and that might look like a gummy bear or a flapjack.

I think you could almost compare it to what a person with diabetes would typically experience. Everyone knows that if you have diabetes and you have low blood sugar, you need something that’s going to get that up, like a shot of orange juice or one of those glucose tabs. And I think the same thing applies to the athlete: when your blood sugar is that low, you need something that’s going to act fast. Of course, if you’re consuming consistent carbohydrates throughout your ride, you hopefully won’t get to that point.


Once you’re back from the ride, what sort of recovery nutrition should you be aiming for?

A lot of people will tell you that you have a 30-minute window after your workout to replenish your muscles. But I tell my clients that depending on how hard and long they exercised they have up to two hours. So commonly, if you have a big ride, and you get back and know you’re physically tired, you might not be able to stomach chicken, rice and broccoli. So that’s where you know you want a carbohydrate – something that’s not high in fibre – mixed with some protein.

The classic example of a more natural approach is chocolate milk. It’s got the perfect ratio of carbohydrates and protein that you’re looking for. So in terms of that ratio, we usually say four carbohydrates per one protein – a four to one ratio. And that can come in lots of different forms, too; it could even just look like yoghurt, apple or orange juice and a bagel, or maybe the bars, depending on the label. Something like the Trailnuggets Pro product might be that perfect thing to have in your bag even after a workout.


A lot of people talk about post-workout protein…

If you’ve got into the habit of having a protein shake, I think that’s fine because it’s convenient. But at the same time, your body can only digest and absorb 25 to 30 grams at a time, so an excess amount of protein isn’t necessary if it’s just about getting enough to help muscles heal and rebuild glycogen stores.


Hydration also seems like a complicated area. People talk about electrolytes, but is that just salt, or are we talking about something a bit more complicated?

It’s mainly salt in the form of sodium, but during exercise, you can also lose chloride, magnesium and potassium.


And when should you start taking electrolytes on board?

I think you always have to stay ahead of the curve rather than falling behind. If you know you’re going out for a long ride, then sure, having your water bottle concentrated with electrolytes as well as carbohydrates will be important. Going back to the bonk question and combining the two, hitting the wall usually happens because the glycogen stores or your blood glucose gets low; but it can also happen because of dehydration. So taking two or three large gulps every 15 minutes is a great habit to get into.

But for rides of less than an hour, you probably don’t need the jazzy drinks. Go longer than an hour, and you should have some carbohydrates and electrolytes in there. But remember that with carbohydrates, you don’t have to have them in the drink if you’re already eating them in the form of a bar; although I think a lot of athletes find it helpful to have a blend.


There’s a lot of talk about genetics and the complex interplay between nutrition and a person’s intrinsic chemistry.

For sure. And I think one reason why nutrition can get so complicated is because of the influence of genetics, and how someone’s body utilises different nutrients.

But the thing is, we don’t know just by looking at someone what their genetics are. A good example of the genetic tests that we do know about relates to coffee or caffeine. We know that based on the different receptors that individuals carry, some people can be fast metabolisers, and some people can be slow metabolisers. So if you’re a fast metaboliser of caffeine or coffee, you might be able to have a cup before you go on your ride and have an improved athletic performance and a lower risk of heart disease, whereas if you’re a slow metaboliser, you actually might not see any improvement.

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