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How not to Bonk! (Or efficient fuelling for endurance sport events..)

Updated: May 15, 2019

I decided to write this blog following the epic bike ride I had in the Lake District at the weekend; the 'Fred Whitton Challenge'. This is a test of endurance with a capital E; 115 miles over the major Lakeland passes with 3900m of climbing involved. (That's nearly half way up Everest!!) At any age this is no mean feat, at my age it's a triumph!

Heading up Newlands Pass

From a nutritional aspect, it's all about providing your body with the energy, fluids and electrolytes it needs to perform (in my case) for 9 hours. Sounds simple enough, but you'd be amazed how many people get it so very wrong: From the start, I saw people reaching for gels, and that was before the 1st real climb!

So what should you do?

First of all it's not just about feeding on the day; your nutritional plan for the event should start when your training does.. presumably you are taking it seriously. You certainly can't turn up at an event of this magnitude and hope to wing it because it WILL find you out!

A diet consisting of plenty of plant foods and healthy protein will leave little room for junk. The occasional treat ofcourse is fine; who doesn't enjoy a nice piece of cake at a cafe stop? The majority of your carbohydrates should be from wholegrains, leaving the simple sugars for fuelling purposes. This means wholewheat bread, pasta, rice, oats, nuts, seeds, starchy veg such as sweet potato, squash, peas and beans and pulses. Accompanied by at least 2 servings of greens a day, 4 other veggies and 4 servings fruit of which 2 should be tart berries such as blueberries and blackberries.

Your protein may be meat or fish, dairy or vegan. What IS important is that you consume between 1.5-2.0g protein per Kg body weight per day. Eg. A man weighing 70kg needs between 105g and 140g protein daily. And that's not total weight of the portion, it's the protein content of that portion. Eg. a 150g chicken breast contains 46g protein. So if you're a carnivore it's fairly easy to achieve. If you're veggie or vegan however, it does take a bit more planning, and you may need to supplement your diet with a good plant based protein powder.

Why this amount of protein? Pretty simple really; when exercising you are in a state of catabolism, you are literally breaking down muscle fibres and the only way to minimise the loss, and rebuild afterwards is to provide your body with enough building blocks to do it.... protein. If you don't your body will literally start to consume itself (lean tissue) in order to get the amino acids needed for a multitude of body systems. The immune system being one of the first to fail when protein intake is inadequate.

That's your general day to day diet taken care of, so what about the lead up to the event? Carb' loading, does it work? Emphatically YES! Obviously if you carb' load on a daily basis you probably won't notice the difference. BUT you're probably overweight as a result, and most likely missing out on vital nutrients the other food groups provide. Fat for instance, who's a fat phobe? Long gone are the dietary recommendations for a low fat regime (or should be, sadly the food industry and our government are woefully behind the times as far as science based advice is concerned).

Your body NEEDS fat, not only for vitamin D and Omegas, but also for cholesterol (it's not ALL bad) which helps to build healthy cell membranes and sex hormones.

What IS carb loading? It's simply increasing the percentage of carbs to fat you consume during the 2-3 days prior to your event. So if your macro balance previously was 55:25:20 (carb:protein:fat) or thereabouts, you'd need to change to around 70:20:10, or between 6-12 carbs per Kg of bodyweight. Alot depends on your level of fitness, your daily activity and previous intake. If you just increase carbs without making adjustments you'll gain unwanted weight and arrive on the start line feeling like Mr Blobby.. not great!

Good diet generally and Carb loading taken care of you can now focus on planning your event fuel and fluid intake.

As a general rule you will need between 30g and 60 g carbs per hour, this will depend on the severity of your ride, your fitness level and the weather.

1. The more calories you’ll burn, the more carbs you’ll need = no brainer.

If you use a fitness computer of any sort they will usually tell you how many calories you burn during workouts. You will have noticed then that the more demanding the workout, the more calories you burn.

2. The more trained you are, the less carbs you need. A novice rider will need more than a well trained one. Your body becomes more fuel efficient as you train, and will burn a larger percentage of fat for energy.. result!! I followed a Ketogenic (low carb/high fat) diet for a year, and generally try to keep my carbs for training so I’m a fairly efficient fat-burner.

3. If it’s hot you will obviously need more fluids and electrolytes as you will sweat more.

I went down the middle at 45g carbs per hour; I’m well trained, but the Fred Whitton Challenge is an extremely demanding ride!

This is how that looked in food terms....


Black Coffee

6am Breakfast Instant Oats with a banana

From the off 6.45am

2 bottles on the bike, one plain water, one with OTE Energy/Electrolyte mix.

After 2 hours:

Torq Energy bar

One hour later:

Clif Alpine Muesli Energy bar.

50 mile feed station:

Half an egg sandwich ( would have had the other half but they weren't very nice!)

Another piece of flapjack.

Refilled bottles with 1 water and 1 OTE energy drink

1 hour later:

OTE Anytime Caramel energy bar (my favourite!)

84 mile feed station:

Torq Energy bar. Natural caffeine shot. (not a gel) 1/2 banana.

Immediately pre Hardknott Pass (96 miles)

2 Clif shot blok jellies

See the road winding it's way up Hardknott pass?

Top of Hardknott

2 more jellies.

At the Finish:

Bottle water

Cup of tea

Event meal of beans and mushy peas! (Only vegan option available!)


Munching in the car on the way back to the B&B...

Prunes (great antioxidants!)

Walnut halves

Back at the B&B

Plant based protein shake


More water.

Evening meal:

Lentil and spinach Roulade, bean salad, pitta bread and hummus.

Blueberries with coconut milk yogurt.

Plant based protein shake.

More water!

Ofcourse what is right for me on this occasion isn’t necessarily right for everyone, and as I said, needs do vary so much, this is just a guide. Personally I don’t use gels unless it’s an emergency, for me they just disrupt my blood sugar levels too much and start an unpredictable roller coaster of fuelling needs. I find them too sweet, they make me too thirsty and I would much rather eat real food. However, if you’re struggling in the end stages of your ride, there’s nothing better to get you home. The sugar will reach your muscles quickly and give you the boost you need to get to the line.

Practice during training to find what suits you.

You will have noticed my diet is plant based, I decided to experiment with a meat-free March as I'd missed veganary January and had just reached the point where I was sick of meat generally and couldn't afford organic or grass-fed. Nobody is more surprised than I am that I'm still at it, I can honestly say I thought I'd never be vegan but I'm really enjoying the food and the health benefits.

I was dairy-free for intolerance reasons before anyway, so it hasn't really been difficult. I'm not saying I'll never eat meat or fish again, but for now it is suiting me, my body is thanking me for it and I recover much quicker from hard physical efforts than I did before. I know it's not for everyone, and you do need to know what you're doing; it's important to monitor protein and calcium intake for example. Eating out is pretty easy these days.. but event catering can be an issue!!

Recovery continues into the next few days, so try not to neglect your nutrition as soon as the event is over. Sure, treat yourself, you deserve it, but don’t go mad, and do pay attention to protein intake. Neglecting this now will result in a weakened immune system and delayed recovery.

There are many natural (legal!) performance enhancers I haven’t detailed here, such as Beetroot, Cherries and Caffeine. They do work for most people when used properly.

If anyone needs more information and personal assistance with nutrition for performance, please do get in touch.

Whatever your sport, if you want the most from your body you have to put the best nutrition into it. It’s not difficult and makes a huge difference to results and recovery.

Have a great summer and enjoy the outdoors!

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