Have carbs had their chips?

Eating copious quantities of carbs is on page one of The Runner’s Rulebook. But are spuds, pasta et al really the best fuel for our performance, health and body-shape goals

by Fiona Bugler

We need to reassess our relationship with carbs,’ says Laurent Bannock, a performance nutritionist and lecturer who works with both elite and amateur athletes (guruperformance.com). Eating lots of carbohydrates makes you good at metabolising them, explains Bannock – which sounds great until he adds ‘instead of fat’. ‘As an endurance runner you should be using body fat as your primary fuel source, so why do runners get obsessed with consuming carbs?’

Bannock is not alone in questioning the accepted carb doctrine. ‘Skilful marketing has made carbohydrate consumption a religion among athletes,’ says Professor Tim Noakes. ‘They believe that you cannot get energy from anywhere but carbs.’ Noakes – who as author of The Lore of Running (£13.43, Human Kinetics) can safely be classed as a running and sports science heavyweight – recently turned his thinking around on carbs and caused some controversy by advocating a Paleo-style diet (high-protein and low-carb, based on the meat-, nut-, berry- and veg-eating habits of our hunter-gatherer ancestors).

For Noakes, it’s not just about performance, but health too. He argues that some people simply can’t metabolise carbs as efficiently as others. And for the carb-intolerant, eating large quantities won’t just limit fat-burning capacity, it will fail to properly fuel performance, and lead to weight and health problems. For him, the switch was driven by the fact that, despite clocking 200K a week as an ultra runner, his weight was always an issue. He ate the traditional high-carbohydrate, low-fat diet that he had advocated for 33 years, but still ‘expressed his familial predisposition and developed type 2 diabetes’, he says.

‘There’s never reason to eat more than 200g of carbs a day,’ argues Noakes. ‘Some athletes eat 700g a day, and the probable outcome of such high-carb intakes in those with the genetic predisposition is the development of type 2 diabetes – as happened to me.’

Retraining your metabolism

Even if you’re not carrying the carb-intolerant genetic hand, over-consumption of carbs, some argue, can negatively affect your running performance. ‘The body adapts and if you eat lots of carbohydrates, it will become good at metabolising carbohydrates,’ Bannock reiterates. ‘Your body will use the fuel it’s been given and initiate the carb management system. But to see improvements to your endurance-running performance, you
need to retrain your metabolism to get your body used to becoming efficient at using fat as a fuel source – becoming fat-adapted,’ he continues. ‘Improving your ability to burn fat will preserve limited carbohydrate stores for when they’re needed (for instance, at the end of the race), and improving your metabolic efficiency will also boost your health.’

Noakes is reading from the same menu here: ‘Humans are designed to burn fat as the primary fuel during endurance workouts,’ he says. ‘That’s why we store so much of it in our bodies and relatively little carbohydrate. While one might argue that high-intensity exercise of short duration might be improved by a high-carbohydrate diet, the majority of people eating high-carbohydrate diets are involved in prolonged, low-intensity exercise for which fat is the optimum fuel.’

So how do committed ‘carbivores’ retrain their metabolisms to burn fat for fuel? ‘By eating less carbohydrate and more healthy fat, and timing it right,’ says Bannock. ‘It’s what you do on average that affects how your metabolism utilises carbohydrates. So make your daily plate contain 50 per cent starchy vegetables/fruit, and 25 per cent each of lean protein and healthy omega-3-rich fat.’

‘Save the starchy carbs until after your workouts; eat 50 per cent carb/50 per cent protein up to an hour after your run. Then, after two hours, opt for protein, veg, fat and carbs in equal measures,’ explains Bannock. ‘Your body is like a fire, and just after you’ve trained the fire is burning, and this is the time to throw your carbohydrate logs on.’

Other experts agree on the potential performance benefits of limiting your carb intake. ‘New studies suggest it is possible to ‘train’ your muscles to use fat preferentially for fuel by consuming a low-carb diet,’ says Anita Bean, author of The Complete Guide to Sports Nutrition (£10.87, A&C Black). ‘Over time, the muscles will make more fat-burning enzymes and mitochondria,’ she explains. ‘Though low-carb diets will best suit those training for shorter races or those who are pre-diabetic [insulin-resistant].’

To take your carb-limiting strategy a stage further, consider the maxim of ‘train low, race high’. ‘Eating a low-carb diet in training and a high-carb diet 24 hours before a race gives you an advantage of having more fat-burning enzymes, plus more carbs as fuel for your muscles in the latter stages,’ says Bean.

Also pay attention to your intake of energy drinks, which are very high in carbs with 30g or more per 500ml, ‘which you simply don’t need if you’re running at a moderate speed for less than 60 minutes’, says Bean. ‘Then, water is all you need to hydrate.’

Training your metabolism to be ‘fat-adapted’ means you ‘won’t need to ingest sugary sports drinks, because you have all the energy you need in your body’, says Noakes. ‘If you are carbohydrate-adapted, you will probably need to take in sugary drinks during exercise,’ he says. ‘But whether or not drinking sugary drinks during exercise is healthy is another question entirely: there is growing evidence that sugary drinks increase the risk of developing diabetes. Even one can of sugary drink a day is associated with an increased diabetes risk.’

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Discuss this article

I spent three days hiking and running with Haile Gebrselassie (double Olympic Gold medalist) and a couple of 2:06/2:07 marathon runners last week in Southern Ethiopia and was surprised to find their preferred diet is almost exclusively lean red meat some of it raw. There was very little carb.

Posted: 30/06/2013 at 15:38

Raw red meat?

So - this the latest fad? Someone need to sell a book? Kenyans get by on a very simple high carb diet which includes lots of "evil" sugar, and not a lot of meat. What they don't do is over analyze...and also they don't have access to loads of processed junk food etc.

Posted: 30/06/2013 at 21:49

They also rest a lot, by all accounts. If you don't eat carbs, you don't have any energy - simple.

Posted: 02/07/2013 at 12:24

I love the smell of red meat in the morning; smells like Gall stones (Ouch).

Posted: 02/07/2013 at 15:16


and I seriously doubt that people who aren't efficient at carb digestion would become serious endurance athletes anyway. 

And the funny thing thar I have observed on almost all Low-carbers is that they tell you to eat stuff plus VEGS... Sorry? aren't vegs made of carbs?

Posted: 03/07/2013 at 17:53

I just noticed one thing:

The proposition they made is adound 50% carbs and (I suppose) the rest divided equally between fat and potein... however: Isn't this already a 10% more carbs than what's normally suggested: 40% carbs + 30% fat and 30% protein?

So, what do these people call "high carbs"? a diet based on potatoes only?

I am afraid this article is just another one comming from the prestigiuos team of Captain Obvious

Posted: 03/07/2013 at 18:05

I have read this in the actual magazine I got last week (the full article). Some of the statements/quotes need to be subject to far greater peer review and scrutiny - especially the stuff about saturated fats.

Posted: 04/07/2013 at 14:30

I think back to the days of yore when the Oxford and Cambridge boat crews were allowed sppecial diets at the communal eating table. As far as I know, they still are. The commanded fuel was enormous quantities of steak and eggs, washed down with milk.

Before you cry wolf, think a little more carefully. Their breakfast was a POST EXERCISE refuel.

I also, perchance, stayed in a hotel in Italy when a cycle team visited, on tour. They were fed with treble quantities of pasta. Draw your own conclusions..

Posted: 04/07/2013 at 22:27

Amusing article and comments . Red meat = gall stones ? really ? 

Not a particularly healthy alternative diet in the article either . No saturated fat / no mono fat = bad hormone profile . No links to boring NHS articles about heart disease either please (sponsored by flora margarine probably) .

Yes , the elite Africans do eat a simple starch based diet with little protein , that doesn't mean recreational runners should follow suit unless they are trying desperately to get ill . 

These articles are out there to confuse and they always succeed .

My advice to myself ? Be a competitive long distance runner = up the starchy carbs , lower the sugary junk , keep protein and sat fat to medium/low . Aim for longevity and health with the occasional recreational run = carbs right down , protein medium and sat and mono fat up high (we evolved very well like this I believe) . Oh , most importantly don't forget some O3's , though tinned oily fish does stink the kitchen out .

Posted: 05/07/2013 at 11:51

"And the funny thing thar I have observed on almost all Low-carbers is that they tell you to eat stuff plus VEGS... Sorry? aren't vegs made of carbs?"

Isn't the clue in the term 'low carb', rather than 'no carb'...?
I'm not a follower of it as I love bread too much, but the message I take from it, is eat less processed food, which doesn't sound unreasonable to me.

Posted: 07/07/2013 at 09:23

Very interesting read and so helpful for me as one of these guys that have a 24% body fat and pre diabetic sugars and do upto 40m cardio a week.  So I will take some of this on board and try and slow the rate of my Type 2 demise, by taking some of the higher fats and proteins and dropping the over carbed high GI foods and  try and add the lower veg carbs with lower GI readings.

Thanks for a good post.

Posted: 08/07/2013 at 02:10

I've been on low carb since Feb (5 months) and with 2-3 days training a week I just ran a 1:47 half marathon (two minutes off my PB). I most likely would have beaten my PB if I had trained more. I had been restricting myself to less than 200g of carbs a day and during the race I never ran out of energy and felt great afterwards. 

A week later I cycled 76k (a little over 3hrs 30mins) with no carbs (just almonds, walnuts and water) and again still felt full of energy.

To those that say you need carbs for energy, sorry, that is not correct!

Posted: 18/07/2013 at 10:58

"A week later I cycled 76k (a little over 3hrs 30mins) with no carbs (just almonds, walnuts and water) and again still felt full of energy."

That's not really no carbs is it?  Given that Almonds are 25% carbohydrate and walnuts have almost the same amount of carbohydrates as they do protein.

Posted: 18/07/2013 at 12:16

I heard Haile ran his 2.03.59 whilst in ketosis so he didn't hit the wall.

Posted: 18/07/2013 at 21:45

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